| 1. |
- Pages-Diaz, J., et al.
(författare)
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Semi-continuous co-digestion of solid cattle slaughterhouse wastes with other waste streams: Interactions within the mixtures and methanogenic community structure
- 2015
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Ingår i: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 273, s. 28-36
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Tidskriftsartikel (refereegranskat)abstract
- The performance of the anaerobic co-digestion process is strongly related to the characteristics of the substrates utilized. In this work, the impact of mixture interactions, i.e., synergy and antagonism, previously observed in batch operation mode were evaluated under semi-continuous co-digestion of slaughterhouse waste (SB) and its different combinations with manure (M), various crops (VC), and municipal solid waste (MSW). The effects on the process performance and the microbial community structure were investigated. The digestion of SB failed at an OLR of 0.9 gVS L-1 d(-1). However, stable performance with higher loadings was observed for mixtures that displayed synergy obtained earlier in the batch mode (i.e., SB + M, SB + VC + MSW). Bacterial and Archaeal groups increased for the SB + M and SB + VC + MSW, compared with the digestion of SB alone and that for SB + VC. The combination that showed antagonistic effects (SB + VC) resulted in unstable operation and poor representation of methanogens. It was proved that synergetic or antagonistic effects observed in batch mode due to the different mixture compositions could be correlated to process performance, as well as the development of the microbial community structure during semi-continuous operation.
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| 2. |
- Pour Bafrani, Mohammad, 1981, et al.
(författare)
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Production of biofuels, limonene and pectin from citrus wastes
- 2010
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Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 101:11, s. 4246-4250
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Tidskriftsartikel (refereegranskat)abstract
- Production of ethanol, biogas, pectin and limonene from citrus wastes (CWs) by an integrated process was investigated. CWs were hydrolyzed by dilute-acid process in a pilot plant reactor equipped with an explosive drainage. Hydrolysis variables including temperature and residence time were optimized by applying a central composite rotatable experimental design (CCRD). The best sugar yield (0.41 g/g of the total dry CWs) was obtained by dilute-acid hydrolysis at 150 degrees C and 6 min residence time. At this condition, high solubilization of pectin present in the CWs was obtained, and 77.6% of total pectin content of CWs could be recovered by solvent recovery. Degree of esterification and ash content of produced pectin were 63.7% and 4.23%, respectively. In addition, the limonene of the CWs was effectively removed through flashing of the hydrolyzates into an expansion tank. The sugars present in the hydrolyzates were converted to ethanol using baker's yeast, while an ethanol yield of 0.43 g/g of the fermentable sugars was obtained. Then, the stillage and the remaining solid materials of the hydrolyzed CWs were anaerobically digested to obtain biogas. In summary, one ton of CWs with 20% dry weight resulted in 39.641 ethanol, 45 m(3) methane, 8.91 limonene, and 38.8 kg pectin.
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| 3. |
- Teghammar, Anna, 1981, et al.
(författare)
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Substrate Characteristic Analysis for Anaerobic Digestion: A Study on Rice and Triticale Straw
- 2012
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Ingår i: BioResources. - : North Carolina State University: College of Natural Resources. - 1930-2126 .- 1930-2126. ; 7:3, s. 3921-3934
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Tidskriftsartikel (refereegranskat)abstract
- Different substrate characteristic analyses have been studied on rice and triticale straw pretreated with NMMO (N-methylmorpholine-N-oxide) prior to biogas production. Simons' stain, water retention value (WRV), and enzymatic adsorption were used to measure the change in the accessible surface area of the lignocellulosic substrates. FTIR was used to measure the change in cellulosic crystallinity and Time-of-Flight-Secondary-Ion-Spectroscopy (ToF-SIMS) to measure the ratio of cellulose to lignin on the sample surface. All methods showed increased accessible surface area and a decrease in crystallinity after the pretreatments. These qualities were linked to improved biogas production. In the future, the tested methods could replace the time-consuming methane potential analysis to predict the methane production of lignocellulosic materials. Simons' stain, enzymatic adsorption, and crystallinity measurement by FTIR can be regarded as the recommended methods for the prediction of the improved biogas production as a result of the pretreatment.
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| 4. |
- Chandolias, Konstantinos, et al.
(författare)
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Protective effect of a reverse membrane bioreactor against toluene and naphthalene in anaerobic digestion
- 2022
-
Ingår i: Biotechnology and Applied Biochemistry. - : Wiley. - 1470-8744 .- 0885-4513. ; 69:3, s. 1267 -1274
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Tidskriftsartikel (refereegranskat)abstract
- Raw syngas contains tar contaminants including toluene and naphthalene, which inhibit its conversion to methane. Cell encasement in a hydrophilic reverse membrane bioreactor (RMBR) could protect the cells from hydrophobic contaminants. This study aimed to investigate the inhibition of toluene and naphthalene and the effect of using RMBR. In this work, toluene and naphthalene were added at concentrations of 0.5–1.0 and 0.1–0.2 g/L in batch operation. In continuous operation, concentration of 0–6.44 g/L for toluene and 0–1.28 g/L for naphthalene were studied. The results showed that no inhibition was observed in batch operation for toluene and naphthalene at concentrations up to 1 and 0.2 g/L, respectively. In continuous operation of free cell bioreactors (FCBRs), inhibition of toluene and naphthalene started at 2.05 and 0.63 g/L, respectively. When they were present simultaneously, inhibition of toluene and naphthalene occurred at concentrations of 3.14 and 0.63 g/L, respectively. In continuous RMBRs, no inhibition for toluene and less inhibition for naphthalene were observed, resulting in higher methane production from RMBR than that of FCBR. These results indicated that RMBR system gave a better protection effect against inhibitors compared with FCBR.
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| 5. |
- Dasa, Kris, 1989, et al.
(författare)
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Inhibitory Effect of Long-Chain Fatty Acids on Biogas Production and the Protective Effect of Membrane Bioreactor
- 2016
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Ingår i: BioMed Research International. - : Hindawi Limited. - 2314-6133 .- 2314-6141. ; 2016:ID:7263974, s. 9 pages-
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Tidskriftsartikel (refereegranskat)abstract
- Anaerobic digestion of lipid-containing wastes for biogas production is often hampered by the inhibitory effect of long-chain fatty acids (LCFAs). In this study, the inhibitory effects of LCFAs (palmitic, stearic, and oleic acid) on biogas production as well as the protective effect of a membrane bioreactor (MBR) against LCFAs were examined in thermophilic batch digesters. The results showed that palmitic and oleic acid with concentrations of 3.0 and 4.5 g/L resulted in >50% inhibition on the biogas production, while stearic acid had an even stronger inhibitory effect. The encased cells in the MBR system were able to perform better in the presence of LCFAs. This system exhibited a significantly lower percentage of inhibition than the free cell system, not reaching over 50% at any LCFA concentration tested.
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| 6. |
- Gmoser, Rebecca, 1990-, et al.
(författare)
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From stale bread and brewers spent grain to a new food source using edible filamentous fungi
- 2020
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Ingår i: Bioengineered Bugs. - : Informa UK Limited. - 2165-5979 .- 2165-5987. ; 11:1, s. 582-598
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Tidskriftsartikel (refereegranskat)abstract
- By-products from the food sector with a high load of organic matter present both a waste-handling problem related to expenses and to the environment, yet also an opportunity. This study aims to increase the value of stale bread and brewers spent grain (BSG) by re-introducing these residues to the food production chain by converting them to new protein-enriched products using the edible filamentous fungi Neurospora intermedia and Rhizopusoryzae. After 6 days of solid state fermentation (at 35°C, with a95% relative humidity and moisture content of 40% in the substrate) on stale bread, a nutrient-rich fungal-fermented product was produced. The total protein content, as analyzed by total amino acids, increased from 16.5% in stale sourdough bread to 21.1% (on dry weight basis) in the final product with an improved relative ratio of essential amino acids. An increase in dietary fiber, minerals (Cu, Fe, Zn) and vitamin E, as well as an addition of vitamin D2 (0.89 µg/g dry weight sample) was obtained compared with untreated stale bread. Furthermore, addition of BSG to the sourdough bread with the aim to improve textural changes after fermentation showed promising outcomes. Cultivation of N. intermedia or R. oryzae on stale sourdough bread mixed with 6.5% or 11.8% BSG, respectively, resulted in fungal-fermented products with similar textural properties to a commercial soybean burger. Bioconversion of stale bread and BSG by fungal solid state fermentation to produce a nutrient-enriched food product was confirmed to be a successful way to minimize food waste and protein shortage.
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| 7. |
- Kurniawan, Tonny, et al.
(författare)
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Semi-continuous reverse membrane bioreactor in two-stage anaerobic digestion of citruswaste
- 2018
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Ingår i: Materials. - : MDPI AG. - 1996-1944. ; 11:8
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Tidskriftsartikel (refereegranskat)abstract
- The presence of an antimicrobial compound called D-Limonene in citrus waste inhibits methane production from such waste in anaerobic digestion. In this work, a two-stage anaerobic digestion method is developed using reverse membrane bioreactors (rMBRs) containing cells encased in hydrophilic membranes. The purpose of encasement is to retain a high cell concentration inside the bioreactor. The effectiveness of rMBRs in reducing cell washout is evaluated. Three different system configurations, comprising rMBRs, freely suspended cells (FCs), and a combination of both (abbreviated to rMBR-FCs), are incubated at three different organic loading rates (OLRs) each, namely 0.6, 1.2, and 3.6 g COD/(L cycle). Incubation lasts for eight feeding cycles at 55 °C. Methane yield and biogas composition results show that rMBRs perform better than rMBR-FCs and FCs at all three OLRs. Volatile fatty acid profiles and H2production show that the reactors are working properly and no upset occurs. Additionally, a short digestion time of 4 days can be achieved using the rMBR configuration in this study.
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| 8. |
- Lennartsson, Patrik R, 1983, et al.
(författare)
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Ethanol production from lignocellulose by the dimorphic fungus Mucor indicus
- 2008
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Ingår i: World Bioenergy. Jönköping, Sweden, 27-29 May, 2008.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Ethanol production from dilute-acid hydrolyzate by the dimorphic fungus Mucor indicus was investigated. A mixture of different forest wood chips dominated by spruce was hydrolyzed with 0.5 g/L sulfuric acid at 15 bar for 10 min, yielding different sugars including galactose, glucose, mannose, and xylose, but also different fermentation inhibitors such as acetic acid, furfural, hydroxymethyl furfural (HMF), and phenolic compounds. We induced different morphological growth of M. indicus from purely filamentous, mostly filamentous, mostly yeast-like to purely yeast-like. The different forms were then ysed to ferment the hydrolyzate. They tolerated the presence of the inhibitors under anaerobic batch cultivation well and the ethanol yield was 430-440 g/kg consumed sugars. The ethanol productivity depended on the morphology. Judging from these results, we conclude that M. indicus is useful for ethanol production from toxic substrates independent of its morphology.
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| 9. |
- Lukitawesa, Lukitawesa, et al.
(författare)
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Effect of effluent recirculation on biogas production using two-stage anaerobic digestion of citrus waste
- 2018
-
Ingår i: Molecules. - : MDPI AG. - 1420-3049 .- 1420-3049 .- 1431-5157. ; 23:12
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Tidskriftsartikel (refereegranskat)abstract
- Citrus waste is a promising potential feedstock for anaerobic digestion, yet the presence of inhibitors such as D-limonene is known to limit the process. Effluent recirculation has been proven to increase methane yield in a semi-continuous process for recalcitrant material, but it has never been applied to toxic materials. This study was aimed to investigate the effect of recirculation on biogas production from citrus waste as toxic feedstock in two-stage anaerobic digestion. The first digestion was carried out in a stirred tank reactor (STR). The effluent from the first-stage was filtered using a rotary drum filter to separate the solid and the liquid phase. The solid phase, rich in hydrophobic D-limonene, was discarded, and the liquid phase containing less D-limonene was fed into the second digester in an up-flow anaerobic sludge bed (UASB) reactor. A high organic loading rate (OLR 5 g VS/(L·day)) of citrus waste was fed into the first-stage reactor every day. The effluent of the first-stage was then fed into the second-stage reactor. This experiment was run for 120 days. A reactor configuration without recirculation was used as control. The result shows that the reactor with effluent recirculation produced a higher methane yield (160–203 NmL/g·VS) compared to that without recirculation (66–113 NmL/g·VS). More stable performance was also observed in the reactor with recirculation as shown by the pH of 5–6, while without recirculation the pH dropped to the range of 3.7–4.7. The VS reduction for the reactor with recirculation was 33–35% higher than that of the control without recirculation. Recirculation might affect the hydrolysis-acidogenesis process by regulating pH in the first-stage and removing most of the D-limonene content from the substrate through filtration.
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| 10. |
- Lukitawesa, Lukitawesa, et al.
(författare)
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Inhibition of patchouli oil for anaerobic digestion and enhancement in methane production using reverse membrane bioreactors.
- 2017
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Ingår i: Renewable energy. - : Elsevier Ltd.. - 0960-1481 .- 1879-0682.
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Tidskriftsartikel (refereegranskat)abstract
- Patchouli oil is an essential oil extd. from arom. crop Pogostemon cablin and is widely used in perfumery industry, food industry, and/or even as medicine. The leaves have 4.6% oil that is extd. by steam, but remains an enormous amt. of wastes contg. ca 0.8% oil. Patchouli waste is an interesting substrate for methane prodn. However, the oil has been found to have antibacterial activity. The inhibition of patchouli oil on anaerobic digestion was investigated in this study under thermophilic conditions (55 °C). The patchouli oil showed antibacterial effect, where addn. of 0.05, 0.5 and 5 g/L patchouli oil reduced biogas prodn. by 16.2%, 27.2% and 100% resp. As patchouli oil is a lipophilic compd., hydrophilic polyvinylidene difluoride (PVDF) membrane was used to protect the microorganisms against this inhibitor in a reverse membrane bioreactor (rMBR) system. The methane yield of fresh plant and waste were 86 and 179 NmL CH4/gVS, resp. when using free cells. Although using solely an rMBR did not give significant rise to methane yield, the combination rMBR and free cell strategy to protect part of the digesting microorganisms against this inhibitor considerably enhanced the methane prodn. by 73% for fresh patchouli plant, compared to digestion using free cells. [on SciFinder(R)]
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| 11. |
- Marhendraswari, M. B.D., et al.
(författare)
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Production of edible fungal (Rhizopus delemar CBS 145940) biomass from organosolv-pretreated oil palm empty fruit bunch (OPEFB) in submerged fermentation
- 2020
-
Ingår i: IOP Conference Series: Materials Science and Engineering. - : Institute of Physics (IOP). - 1757-8981 .- 1757-899X. ; 991:1
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Konferensbidrag (refereegranskat)abstract
- Accumulation of oil palm empty fruit bunches (OPEFB) from palm oil industry poses challenges for the disposal process, which leads to environmental damage. For this reason, valorization of OPEFB fractions to produce edible fungal biomass was carried out in this research. The fungus was Rhizopus delemar CBS 145940, which is an edible fungus, Indonesian indigenous, and is favorable for the production of several end products. Organosolv pretreatment was first conducted on OPEFB using ethanol (50%) as the solvent. Enzymatic hydrolysis was then performed using Cellic® Ctec3 on the pretreated-OPEFB fractions. Hydrolyzates from cellulose-rich fraction, slurry (a mixture of cellulose-rich fraction and hemicellulose-rich fraction), and hemicellulose-rich fraction were used as the cultivation media for fungal growth. The corresponding yield of fungal biomass from each medium was 0.62 ± 0.07 g/g glucose; 0.41 ± 0.02; and 0.61 ± 0.13 g/g fermentable sugars, respectively. These results showed that Rhizopus delemar CBS 145940 could be grown in all the hydrolyzates from the OPEFB fractions. Nevertheless, in order to obtain higher fungal biomass, supplementation of nutrition was needed.
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| 12. |
- Millati, Ria, 1972, et al.
(författare)
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Anaerobic digestion of citrus waste using two-stage membrane bioreactor
- 2018
-
Ingår i: IOP Conference Series: Materials Science and Engineering. - 1757-8981 .- 1757-899X. ; 316:1
-
Konferensbidrag (refereegranskat)abstract
- Anaerobic digestion is a promising method to treat citrus waste. However, the presence of limonene in citrus waste inhibits anaerobic digestion process. Limonene is an antimicrobial compound and could inhibit methane forming bacteria that takes a longer time to recover than the injured acid forming bacteria. Hence, volatile fatty acids will be accumulated and methane production will be decreased. One way to solve this problem is by conducting anaerobic digestion process into two stages. The first step is aimed for hydrolysis, acidogenesis, and acetogenesis reactions and the second stage is aimed for methanogenesis reaction. The separation of the system would further allow each stage in their optimum conditions making the process more stable. In this research, anaerobic digestion was carried out in batch operations using 120 ml-glass bottle bioreactors in 2 stages. The first stage was performed in free-cells bioreactor, whereas the second stage was performed in both bioreactor of free cells and membrane bioreactor. In the first stage, the reactor was set into 'anaerobic' and 'semi-aerobic' conditions to examine the effect of oxygen on facultative anaerobic bacteria in acid production. In the second stage, the protection of membrane towards the cells against limonene was tested. For the first stage, the basal medium was prepared with 1.5 g VS of inoculum and 4.5 g VS of citrus waste. The digestion process was carried out at 55°C for four days. For the second stage, the membrane bioreactor was prepared with 3 g of cells that were encased and sealed in a 3×6 cm 2 polyvinylidene fluoride membrane. The medium contained 40 ml basal medium and 10 ml liquid from the first stage. The bioreactors were incubated at 55°C for 2 days under anaerobic condition. The results from the first stage showed that the maximum total sugar under 'anaerobic' and 'semi-aerobic' conditions was 294.3 g/l and 244.7 g/l, respectively. The corresponding values for total volatile fatty acids were 3.8 g/l and 2.9 g/l, respectively. Methane production of citrus waste taken from the first stage under 'anaerobic' condition in membrane and free-cells bioreactors was 11.2 Nml and 7.2 Nml, respectively. Whereas, methane production of citrus waste taken from the first stage under 'semi-aerobic' condition in membrane and free-cells bioreactors was 8.8 Nml and 5.7 Nml, respectively. It can be seen from the results of the first stage that volatile fatty acids from 'anaerobic' condition was higher than that of 'semi-aerobic' condition. The absence of oxygen provides the optimal condition for growth and metabolism of facultative and obligatorily anaerobic bacteria in the first stage. Furthermore, polyvinylidene fluoride membrane was able to protect the cells from antimicrobial compounds.
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| 13. |
- Millati, Ria, 1972, et al.
(författare)
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Performance of Rhizopus, Rhizomucor, and Mucor in ethanol production from glucose, xylose, and wood hydrolyzates
- 2005
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Ingår i: Enzyme and microbial technology. - : Elsevier BV. - 0141-0229 .- 1879-0909. ; 36:2-3, s. 294-300
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Tidskriftsartikel (refereegranskat)abstract
- In searching for ethanol producing microorganisms also capable of fermenting pentoses, nine zygomycetes strains including three strains of Rhizopus oryzae, Mucor corticolous, M. hiemalis, M. indicus, Rhizomucor pusillus, R. miehei, and zygomycete IT were examined. Each strain was cultivated on glucose, xylose or dilute-acid hydrolyzate (DAH) as carbon sources, and the production of ethanol, lactic acid, glycerol, xylitol, and succinic acid were investigated. Great similarities but also conspicuous differences were seen between the species, to some extent linked to the genera. All strains were capable of growing on glucose or xylose as single carbon source. With the exception of the two Rhizomucor strains, all produced ethanol. All the strains produced glycerol as by-product, while Rhizopus and Rhizomucor but not Mucor produced lactic acid in significant amounts. All Mucor and Rhizopus strains and one strain of Rhizomucor produced xylitol in the xylose medium, but no xylitol was detected after growth on DAH. All Mucor and two R. oryzae strains were capable of growing on DAH. Two Mucor species, M. hiemalis and M. indicus showed greater ethanol production than the other strains. The ethanol yields by M. hiemalis on glucose, xylose, and DAH were 0.39, 0.18, and 0.44 g/g, respectively, whereas the corresponding results for M. indicus were 0.39, 0.22, and 0.44 g/g. The strains also rapidly consumed hydroxymethyl furfural present in DAH.
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| 14. |
- Mondylaksita, Kinanthi, et al.
(författare)
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Enhanced volatile fatty acid production from oil palm empty fruit bunch through acidogenic fermentation - A novel resource recovery strategy for oil palm empty fruit bunch
- 2021
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Ingår i: Fermentation. - : MDPI AG. - 2311-5637. ; 7:4
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Tidskriftsartikel (refereegranskat)abstract
- The glucan-rich fraction, hemicellulosic compounds-rich fraction, and a mixture of both fractions obtained from organosolv pretreatment of oil palm empty fruit bunch (OPEFB) were used as substrates to produce volatile fatty acids (VFAs) in acidogenic fermentation. In this study, the effects of medium adjustment (carbon to nitrogen ratio and trace elements supplementation) and methanogenesis inhibition (through the addition of 2-bromoethanesulfonate or by heat shock) to enhance VFAs yield were investigated. The highest VFA yield was 0.50 ± 0.00 g VFAs/g volatile solid (VS), which was obtained when methanogens were inhibited by heat shock and cultivated in a mixture of glucan-rich and hemicellulosic compounds-rich fractions. Under these conditions, the fermentation produced acetic acid as the only VFA. Based on the results, the mass balance of the whole process (from pretreatment and fermentation) showed the possibility to obtain 30.4 kg acetic acid and 20.3 kg lignin with a 70% purity from 100 kg OPEFB.
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| 15. |
- Mondylaksita, Kinanthi, et al.
(författare)
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Recovery of High Purity Lignin and Digestible Cellulose from Oil Palm Empty Fruit Bunch Using Low Acid-Catalyzed Organosolv Pretreatment
- 2020
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Ingår i: Agronomy. - : MDPI AG. - 2073-4395. ; 10:5
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Tidskriftsartikel (refereegranskat)abstract
- The lignocellulosic residue from the palm oil industry, oil palm empty fruit bunch (OPEFB), represents a challenge to both producing industries and environment due to its disposal difficulties. Alternatively, OPEFB can be used for the production of valuable products if pretreatment methods, which overcome OPEFB recalcitrance and allow tailored valorization of all its carbohydrates and lignin, are developed. Specifically, high-value applications for lignin, to increase its contribution to the feasibility of lignocellulosic biorefineries, demand high-purity fractions. In this study, acid-catalyzed organosolv using ethanol as a solvent was used for the recovery of high-purity lignin and digestible cellulose. Factors including catalyst type and its concentration, temperature, retention time, and solid-to-liquid (S/L) ratio were found to influence lignin purity and recovery. At the best conditions (0.07% H2SO4, 210 degrees C, 90 min, and S/L ratio of 1:10), a lignin purity and recovery of 70.6 +/- 4.9% and 64.94 +/- 1.09%, respectively, were obtained in addition to the glucan-rich fraction. The glucan-rich fraction showed 94.06 +/- 4.71% digestibility within 18 h at an enzyme loading of 30 filter paper units (FPU) /g glucan. Therefore, ethanol organosolv can be used for fractionating OPEFB into three high-quality fractions (glucan, lignin, and hemicellulosic compounds) for further tailored biorefining using low acid concentrations. Especially, the use of ethanol opens the possibility for integration of 1st and 2nd generation ethanol benefiting from the separation of high-purity lignin.
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| 16. |
- Rousta, Neda, et al.
(författare)
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Production of fungal biomass from oat flour for the use as a nutritious food source
- 2022
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Ingår i: NFS Journal. - : Elsevier BV. - 2352-3646. ; 29, s. 8-15
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Tidskriftsartikel (refereegranskat)abstract
- Fermentation can be a powerful tool for developing new sustainable foods with increased nutritional value and fermented microbial biomass derived from filamentous fungi is a promising example. This study investigates the nutritional profile of edible Aspergillus oryzae biomass produced under submerged fermentation (SmF) using oat flour as a substrate. The fermentation occurred in a 1m3 airlift bioreactor during 48 h at 35 °C and the nutritional profile of the produced fungal biomass in terms of amino acids, fatty acids, minerals (Fe, Zn, Cu, Mn), vitamins (E, D2), and dietary fiber was compared to oat flour as well as pure fungal biomass grown on semi-synthetic medium. The total amount of amino acids increased from 11% per dry weight (dw) in oat flour to 23.5% dw in oat fungal biomass with an improved relative ratio of essential amino acids (0.37 to 0.42). An increase in dietary fibers, minerals (Fe, Zn, Cu), vitamin E, as well as vitamin D2 were also obtained in the oat fungal biomass compared to oat flour. Moreover, the short chain omega-3 α-linolenic acid (ALA) and omega-6 linoleic acid (LA) values increased from 0.6 to 8.4 and 21.7 to 68.4 (mg/g dry weight sample), respectively, in oat fungal biomass. The results indicate that fungal biomass grown on oat flour could have a potential application in the food industry as a nutritious source for a wide variety of products.
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| 17. |
- Sar, Taner, Postdoctoral Researcher, 1989-, et al.
(författare)
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Demo-scale production of protein-rich fungal biomass from potato protein liquor for use as innovative food and feed products
- 2022
-
Ingår i: Food Bioscience. - : Elsevier BV. - 2212-4292 .- 2212-4306. ; 47
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Tidskriftsartikel (refereegranskat)abstract
- Innovative food and feed products have recently attracted the attention of both producers and consumers. Filamentous fungi are important biomass producers with their high protein contents. In this study, fungal biomass production from edible potato protein liquor (PPL), generated during starch production processes, was investigated through different fungal strains (Rhizopus oryzae, R. oligosporus, R. delemar, Aspergillus oryzae and Neurospora intermedia). The effects of PPL concentration, incubation time, initial pH, and cultivation conditions (in shake flaks and different scale reactors) were examined to determine the amount of biomass and its crude protein level. It was determined that the fungal biomass produced by R. delemar in industrial scale contained 53% crude protein. For this strain, the amino acid and fatty acid profiles as well as metals (iron, manganese, copper, and zinc) of the produced biomass were also investigated to assess possible use as a food or feed source. The R. delemar fungal biomass can be a promising raw material for feed and food production, for example, considering its protein and fatty acid profiles with 41% essential amino acids and 33% polyunsaturated fatty acids.
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| 18. |
- Sárvári Horváth, Ilona, 1960, et al.
(författare)
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Effects of furfural on the respiratory metabolism of Saccharomyces cerevisiae in glucose-limited chemostats
- 2003
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Ingår i: Applied and Environmental Microbiology. - 0099-2240 .- 1098-5336. ; 69:7, s. 4076-4086
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Tidskriftsartikel (refereegranskat)abstract
- Effects of furfural on the aerobic metabolism of the yeast Saccharomyces cerevisiae were studied by performing chemostat experiments, and the kinetics of furfural conversion was analyzed by performing dynamic experiments. Furfural, an important inhibitor present in lignocellulosic hydrolysates, was shown to have an inhibitory effect on yeast cells growing respiratively which was much greater than the inhibitory effect previously observed for anaerobically growing yeast cells. The residual furfural concentration in the bioreactor was close to zero at all steady states obtained, and it was found that furfural was exclusively converted to furoic acid during respiratory growth. A metabolic flux analysis showed that furfural affected fluxes involved in energy metabolism. There was a 50% increase in the specific respiratory activity at the highest steady-state furfural conversion rate. Higher furfural conversion rates, obtained during pulse additions of furfural, resulted in respirofermentative metabolism, a decrease in the biomass yield, and formation of furfuryl alcohol in addition to furoic acid. Under anaerobic conditions, reduction of furfural partially replaced glycerol formation as a way to regenerate NAD+. At concentrations above the inlet concentration of furfural, which resulted in complete replacement of glycerol formation by furfuryl alcohol production, washout occurred. Similarly, when the maximum rate of oxidative conversion of furfural to furoic acid was exceeded aerobically, washout occurred. Thus, during both aerobic growth and anaerobic growth, the ability to tolerate furfural appears to be directly coupled to the ability to convert furfural to less inhibitory compounds.
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| 19. |
- Sues, Anna, et al.
(författare)
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Ethanol production from hexoses, pentoses, and dilute-acid hydrolyzate by Mucor indicus
- 2005
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Ingår i: FEMS Yeast Research. - : Oxford University Press (OUP). - 1567-1356 .- 1567-1364. ; 5:6-7, s. 669-676
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Tidskriftsartikel (refereegranskat)abstract
- Consumption of hexoses and pentoses and production of ethanol by Mucor indicus were investigated in both synthetic media and dilute-acid hydrolyzates. The fungus was able to grow in a poor medium containing only carbon, nitrogen, phosphate, potassium, and magnesium sources. However, the cultivation took more than a week and the ethanol yield was only 0.2 g g -1 . Enrichment of the medium by addition of trace metals, particularly zinc and yeast extract, improved the growth rate and yield, such that the cultivation was completed in less than 24 h and the ethanol and biomass yields were increased to 0.40 and 0.20 g g -1 , respectively. The fungus was able to assimilate glucose, galactose, mannose, and xylose, and produced ethanol with yields of 0.40, 0.34, 0.39, and 0.18 g g -1 , respectively. However, arabinose was poorly consumed and no formation of ethanol was detected. Glycerol was the major by-product in the cultivation on the hexoses, while formation of glycerol and xylitol were detected in the cultivation of the fungus on xylose. The fungus was able to take up the sugars present in dilute-acid hydrolyzate as well as the inhibitors, acetic acid, furfural, and hydroxymethyl furfural. M. indicus was able to grow under anaerobic conditions when glucose was the sole carbon source, but not on xylose or the hydrolyzate. The yield of ethanol in anaerobic cultivation on glucose was 0.46 g g -1 . © 2004 Federation of European Microbiological Societies. Published by Elsevier B.V. All rights reserved.
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| 20. |
- Taherzadeh Esfahani, Mohammad, 1965, et al.
(författare)
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Continuous Cultivation of Dilute-Acid Hydrolysates to Ethanol by Immobilized Saccharomyces cerevisiae
- 2001
-
Ingår i: Applied Biochemistry and Biotechnology. - 0273-2289 .- 1559-0291. ; 95:1, s. 45-57
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Tidskriftsartikel (refereegranskat)abstract
- The continuous cultivation of immobilized Saccharomyces cerevisiae CBS 8066 on dilute-acid hydrolysates of forest residuals was investigated. The yeast cells were immobilized in 2–4% Ca-alginate beads. The 2% beads were not stable. However, the 3 and 4% beads were stable for at least 3 wk when an extra resource of calcium ions was available in the medium. The continuous cultivation of a dilute-acid hydrolysate by the immobilized cells at dilution rates of 0.3, 0.5, and 0.6 h−1 resulted in 86, 83, and 79% sugar consumption, respectively, and an ethanol yield between 0.45 and 0.48 g/g. The hydrolysate was fermentable at a dilution rate of 0.1 h−1 in a free-cell system but washed out at a dilution rate of 0.2 h−1. The continuous cultivation of a more inhibiting hydrolysate was not successful by either free- or immobilized-cell systems even at a low dilution rate of 0.07 h−1. However, when the hydrolysate was overlimed, it was fermentable by the immobilized cells at a dilution rate of 0.2 h−1.
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| 21. |
- Talebnia Rowshan, Farid, 1974, et al.
(författare)
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Ethanol production from glucose and dilute-acid hydrolyzates by encapsulated S-cerevisiae
- 2005
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Ingår i: Biotechnology and Bioengineering. - : Wiley. - 0006-3592 .- 1097-0290. ; 90:3, s. 345-353
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Tidskriftsartikel (refereegranskat)abstract
- The performance of encapsulated Saccharomyces cerevisiae CBS 8066 in anaerobic cultivation of glucose, in the presence and absence of furfural as well as in dilute-acid hydrolyzates, was investigated. The cultivation of encapsulated cells in 10 sequential batches in synthetic media resulted in linear increase of biomass up to 106 g/L of capsule volume, while the ethanol productivity remained constant at 5.15 (+/- 0.17) g/L(.)h (for batches 6-10). The cells had average ethanol and glycerol yields of 0.464 and 0.056 g/g in these 10 batches. Addition of 5 g/L furfural decreased the ethanol productivity to a value of 1.31 (+/- 0.10) g/L(.)h with the encapsulated cells, but it was stable in this range for five consecutive batches. On the other hand, the furfural decreased the ethanol yield to 0.41-0.42 g/g and increased the yield of acetic acid drastically up to 0.068 g/g. No significant lag phase was observed in any of these experiments. The encapsulated cells were also used to cultivate two different types of dilute-acid hydrolyzates. While the free cells were not able to ferment the hydrolyzates within at least 24 h, the encapsulated yeast successfully converted glucose and mannose in both of the hydrolyzates in less than 10 h with no significant lag phase. However, since the hydrolyzates were too toxic, the encapsulated cells lost their activity gradually in sequential batches. (c) 2005 Wiley Periodicals, Inc.
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| 22. |
- Talebnia Rowshan, Farid, 1974, et al.
(författare)
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In situ detoxification and continuous cultivation of dilute-acid hydrolyzate to ethanol by encapsulated S. cerevisiae
- 2006
-
Ingår i: Journal of Biotechnology. - : Elsevier. - 0168-1656 .- 1873-4863. ; 125:3, s. 377-384
-
Tidskriftsartikel (refereegranskat)abstract
- Dilute-acid lignocellulosic hydrolyzate was successfully fermented to ethanol by encapsulated Saccharomyces cerevisiae at dilution rates up to 0.5 h-1. The hydrolyzate was so toxic that freely suspended yeast cells could ferment it continuously just up to dilution rate 0.1 h-1, where the cells lost 75% of their viability measured by colony forming unit (CFU). However, encapsulation increased their capacity for in situ detoxification of the hydrolyzate and protected the cells against the inhibitors present in the hydrolyzate. While the cells were encapsulated, they could successfully ferment the hydrolyzate at tested dilution rates 0.1-0.5 h-1, and keep more than 75% cell viability in the worst conditions. They produced ethanol with yield 0.44 ± 0.01 g/g and specific productivity 0.14-0.17 g/(g h) at all dilution rates. Glycerol was the main by-product of the cultivations, which yielded 0.039-0.052 g/g. HMF present in the hydrolyzate was converted 48-71% by the encapsulated yeast, while furfural was totally converted at dilution rates 0.1 and 0.2 h-1 and partly at the higher rates. Continuous cultivation of encapsulated yeast was also investigated on glucose in synthetic medium up to dilution rate 1.0 h-1. At this highest rate, ethanol and glycerol were also the major products with yields 0.43 and 0.076 g/g, respectively. The experiments lasted for 18-21 days, and no damage in the capsules was detected.
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| 23. |
- Uwineza, Clarisse, et al.
(författare)
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Cultivation of edible filamentous fungus Aspergillus oryzae on volatile fatty acids derived from anaerobic digestion of food waste and cow manure
- 2021
-
Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 337
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Tidskriftsartikel (refereegranskat)abstract
- In a circular economy approach, edible filamentous fungi (single cell protein) can be cultivated on volatile fatty acids (VFAs) derived from anaerobic digestion (AD) of organic-rich waste streams. In this study, the effect of pH, concentration/distribution of VFAs, nutrient supplementation, and type of waste on Aspergillus oryzae cultivation on synthetic VFAs, and actual VFAs derived from AD of food waste and cow manure were investigated. The optimal pH for A. oryzae growth on VFAs were 6 and 7 with maximum acetic acid consumption rates of 0.09 g/L. h. The fungus could thrive on high concentrations of acetic (up to 9 g/L) yielding 0.29 g dry biomass/gVFAs(fed). In mixed VFAs cultures, A. oryzae primarily consumed caproic and acetic acids reaching a biomass yield of 0.26 g dry biomass/gVFAs(fed) (containing up to 41% protein). For waste-derived VFAs at pH 6, the fungus successfully consumed 81-100% of caproic, acetic, and butyric acids.
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| 24. |
- Varjani, S., et al.
(författare)
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Bio-based rhamnolipids production and recovery from waste streams : Status and perspectives
- 2021
-
Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 319
-
Tidskriftsartikel (refereegranskat)abstract
- Bio-based rhamnolipid production from waste streams is gaining momentum nowadays because of increasing market demand, huge range of applications and its economic and environment friendly nature. Rhamnolipid type biosurfactants are produced by microorganisms as secondary metabolites and have been used to reduce surface/interfacial tension between two different phases. Biosurfactants have been reported to be used as an alternative to chemical surfactants. Pseudomonas sp. has been frequently used for production of rhamnolipid. Various wastes can be used in production of rhamnolipid. Rhamnolipids are widely used in various industrial applications. The present review provides information about structure and nature of rhamnolipid, production using different waste materials and scale-up of rhamnolipid production. It also provides comprehensive literature on various industrial applications along with perspectives and challenges in this research area.
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| 25. |
- Wainaina, Steven, et al.
(författare)
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Utilization of food waste-derived volatile fatty acids for production of edible Rhizopus oligosporus fungal biomass
- 2020
-
Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 310
-
Tidskriftsartikel (refereegranskat)abstract
- Rhizopus oligosporus is an edible filamentous fungus that can contribute to meet the growing demand for single-cell protein. Volatile fatty acids (VFAs) are favorable potential substrates for producing R. oligosporus biomass due to their capacity to be synthesized from a wide range of low-value organic solid wastes via anaerobic digestion. The goal of this work was to cultivate R. oligosporus using food waste-derived VFAs as the sole carbon source. To maintain the requisite low substrate concentrations, the fed-batch cultivation technique was applied. This resulted in a four-fold improvement in biomass production relative to standard batch cultivation. Maximum biomass yield of 0.21 ± 0.01 g dry biomass/g VFAs COD eq. consumed, containing 39.28 ± 1.54% crude protein, was obtained. In the bubble-column bioreactors, the complete uptake of acetic acid was observed, while the consumptions of caproic and butyric acids reached up to 97.64% and 26.13%, respectively.
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| 26. |
- Wang, Ricky, et al.
(författare)
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In vitro protein digestibility of edible filamentous fungi compared to common food protein sources
- 2023
-
Ingår i: Food Bioscience. - : Elsevier. - 2212-4306 .- 2212-4292. ; 54
-
Tidskriftsartikel (refereegranskat)abstract
- Edible filamentous fungi, as a source of mycoprotein, is an emerging sustainable protein source as it can be cultivated on food-industry sidestreams, thus providing the food system with circularity. However, the digestibility of mycoprotein from different species of fungi is yet to be studied and compared to commonly consumed food proteins derived from muscle. Using the static INFOGEST in vitro gastrointestinal (GI) digestion protocol, but with less pancreatin than the recommended amount to omit high background from enzyme autolysis, this study investigated the protein degree of hydrolysis (DH%) and amino acid accessibility of five species of edible fungi in comparison with salmon fillet, chicken breast, beef tenderloin and casein. Three of the edible fungi species reached protein DH% between 58% ± 2.6% and 62% ± 5.6% during GI digestion compared to chicken, salmon, and beef reaching 62%–67% as well as casein at 55%. The amino acid accessibility of fungi (81%–92%), was comparable to that of salmon, chicken breast, and beef (90%–94%). This study thus indicated that edible fungi is a sustainable and nutritionally sound protein source.
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| 27. |
- Wikandari, Rachma, et al.
(författare)
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Improvement of Biogas Production from Orange Peel Waste by Leaching of Limonene
- 2015
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Ingår i: BioMed Research International. - : Hindawi Limited. - 2314-6133 .- 2314-6141. ; 2015, s. 6-
-
Tidskriftsartikel (refereegranskat)abstract
- Limonene is present in orange peel wastes and is known as an antimicrobial agent, which impedes biogas production when digesting the peels. In this work, pretreatment of the peels to remove limonene under mild condition was proposed by leaching of limonene using hexane as solvent. The pretreatments were carried out with homogenized or chopped orange peel at 20–40°C with orange peel waste and hexane ratio (w/v) ranging from 1 : 2 to 1 : 12 for 10 to 300 min. The pretreated peels were then digested in batch reactors for 33 days. The highest biogas production was achieved by treating chopped orange peel waste and hexane ratio of 12 : 1 at 20°C for 10 min corresponding to more than threefold increase of biogas production from 0.061 to 0.217 m3 methane/kg VS. The solvent recovery was 90% using vacuum filtration and needs further separation using evaporation. The hexane residue in the peel had a negative impact on biogas production as shown by 28.6% reduction of methane and lower methane production of pretreated orange peel waste in semicontinuous digestion system compared to that of untreated peel.
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| 28. |
- Yudianto, David, et al.
(författare)
-
Bioconversion of pretreated wheat straw to ethanol by monascus purpureus CBS 109.07 and fusarium venenatum ATCC 20334 using simultaneous saccharification and fermentation
- 2019
-
Ingår i: Biodiversitas. - : UNS Solo. - 2085-4722 .- 1412-033X. ; 20:8, s. 2229-2235
-
Tidskriftsartikel (refereegranskat)abstract
- Fractions of sulfuric acid-pretreated wheat straw, i.e. solid, liquid, and a mixture of liquid and solid were used as substrates in simultaneous saccharification and fermentation (SSF) process to produce ethanol. The bioconversion was performed by Monascus purpureus CBS 109.07 and Fusarium venenatum ATCC 20334. The highest ethanol yields from solid, liquid and a mixture of solid and liquid fractions by M. purpureus CBS 109.07 were 0.36, 0.41, and 0.37 g/g glucose, respectively. The corresponding values by F. venenatum ATCC 20334 were 0.21, 0.54, 0.35 g/g glucose, respectively.
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| 29. |
- Zamani, Akram, et al.
(författare)
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Effects of partial dehydration and freezing temperature on the morphology and water binding capacity of carboxymethyl chitosan-based superabsorbents
- 2010
-
Ingår i: Industrial and Engineering Chemistry Research. - : American Chemical Society (ACS). - 0196-4321 .- 0888-5885 .- 1520-5045. ; 49:17, s. 8094-8099
-
Tidskriftsartikel (refereegranskat)abstract
- Superabsorbent polymers (SAPs) were prepared from carboxymethyl chitosan (CMCS) cross-linked to a gel, concentrated by partial dehydration in a rotary evaporator (at 70, 85, and 100°C), frozen at -5, -20, and -196°C, and then freeze dried. A 0.9% aqueous solution of CMCS was gelled by addition of glutaraldehyde and partially dehydrated to 1.3-16.8% dry matter (DM) before freeze drying. The water binding capacity (WBC) of the products was up to 171 g/g of superabsorbent. The best results were obtained when 32-81% of the water in the gel was removed in the evaporator at 85-100°C, and the concentrated gel (1.3-4.7% DM) was frozen in liquid nitrogen at -196°C before freeze drying. On average, these SAPs, according to SEM micrographs, had a porous sponge-like structure and absorbed 35 and 32 g/g of saline and urine solutions after 10 min exposure, respectively. The corresponding WBC of two commercial polyacrylate-based SAPs was 34-57 g/g for saline and 30-37 g/g for urine solutions.
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| 30. |
- Abtahi, Z., et al.
(författare)
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Ethanol production by Mucor indicus at high glucose and ethanol concentrations
- 2010
-
Ingår i: Minerva Biotecnologica. - : Edizioni Minerva Medica. - 1120-4826 .- 1827-160X. ; 22:3-4, s. 83-89
-
Tidskriftsartikel (refereegranskat)abstract
- Mucor indicus was cultivated under aerobic and anaerobic conditions to study its tolerance against high concentration of glucose up to 350 g/L and ethanol up to 120 g/L present in the medium. The fungus could grow well even in 350 g/L glucose and produce ethanol, but it was able to assimilate the entire glucose when its concentration was less than 200 g/L. On the other hand, M. indicus produced ethanol as the main product with yield and concentration up to 0.45 g/g and 73 g/L, respectively, while glycerol, its only major byproduct, was produced up to 24 g/L. However, the fungus was not so tolerant against exogenously added ethanol, and it could not grow with more than 40 g/L added ethanol to the culture. Under aerobic conditions, M. indicus displayed different morphology, switching from long filamentous to yeast-like growth forms by increasing initial glucose concentration. This implies that yeast-like growth can be induced by growing M. indicus at high glucose concentration. Under anaerobic conditions, only one yeast-like form was observed.
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| 31. |
- Akinbomi, J G, et al.
(författare)
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Current challenges of high-solid anaerobic digestion and possible measures for its effective applications : a review
- 2022
-
Ingår i: Biotechnology for Biofuels and Bioproducts. - : Springer Nature. - 2731-3654. ; 15:1
-
Forskningsöversikt (refereegranskat)abstract
- The attention that high solids anaerobic digestion process (HS-AD) has received over the years, as a waste management and energy recovery process when compared to low solids anaerobic digestion process, can be attributed to its associated benefits including water conservation and smaller digester foot print. However, high solid content of the feedstock involved in the digestion process poses a barrier to the process stability and performance if it is not well managed. In this review, various limitations to effective performance of the HS-AD process, as well as, the possible measures highlighted in various research studies were garnered to serve as a guide for effective industrial application of this technology. A proposed design concept for overcoming substrate and product inhibition thereby improving methane yield and process stability was recommended for optimum performance of the HS-AD process.
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| 32. |
- Barghi, Hamidreza, 1970, et al.
(författare)
-
Catalytic Synthesis of Bulk Hydrophilic Acetaldehyde-Modified Polyamide 46
- 2014
-
Ingår i: Current Organic Synthesis. - : Bentham Science Publishers Ltd.. - 1570-1794 .- 1875-6271. ; 11:2, s. 288-294
-
Tidskriftsartikel (refereegranskat)abstract
- Hydrophilization of Polyamide 46 (PA46) via modification with acetaldehyde in continuous phase was studied. The chemical modification of PA 46 with acetaldehyde resulted in a water-swollen polymer with hydrophilic property. The polyamide 46 undergoes a nucleophilic addition with acetaldehyde in the presence of aluminum chloride as a catalyst. The extent of bulk hydroxyethylation using AlCl3 resulted in 95.65% modification counted as total N-hydroxyethylated polyamide 46. The modification resulted in improved hydrophilic properties, and a maximum surface free energy of 44.6 mJ/m2 was achieved after 3 h reaction, whereas the unmodified PA46 had a surface free energy of 11.2 mJ/m2. In addition, thermal properties of the polymers were studied using differential scanning calorimetry and thermogravimetric analyses. The functionalization leads to decrease in the crystallization energy from 88 J/g to 51 J/g, while the melting energy is changed from 110 J/g to 53 J/g. Furthermore, the thermal stability of the PA46 to pyrolysis was diminished after hydroxylation.
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| 33. |
- Bidgoli, Hossein, et al.
(författare)
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Effect of carboxymethylation conditions on water binding capacity of chitosan-based superabsorbents
- 2010
-
Ingår i: Carbohydrate Research. - : Elsevier - Pergamon. - 0008-6215 .- 1873-426X. ; 345:18, s. 2683-2689
-
Tidskriftsartikel (refereegranskat)abstract
- A superabsorbent polymer (SAP) from chitosan was provided via carboxymethylation of chitosan, followed by cross-linking with glutaraldehyde and freeze-drying. This work was focused on an investigation of the effects of monochloroacetic acid (MCAA), sodium hydroxide, and reaction time on preparation of carboxymethylchitosan (CMCS). The CMCS products were characterized using FTIR spectroscopy, and their degrees of substitution (DS) were measured using conductimetry and FTIR analysis. The highest DS value was obtained when the carboxymethylation reaction was carried out using 1.75 g MCAA and 1.75 g NaOH per g of chitosan in 4 h. The water solubilities of the CMCS products at various pHs were also evaluated, and the results indicated a significant impact of the reaction parameters on the solubility of CMCS. The CMCSs with the highest DS value resulted in SAPs having the highest water-binding capacity (WBC). TheWBCof the best SAP measured after 10 minexposure in distilled water, 0.9% NaCl solution, synthetic urine, and artificial blood was 104, 33, 30, and 57 g/g, respectively. The WBC of this SAP at pH 2–9 passed a maximum at pH 6.
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| 34. |
- Christia, Abdi, 1991, et al.
(författare)
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Ethanol production from alkali-pretreated oil palm empty fruit bunch by simultaneous saccharification and fermentation with mucor indicus
- 2016
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Ingår i: International Journal of Green Energy. - : Informa UK Limited. - 1543-5075 .- 1543-5083. ; 13:6, s. 566-572
-
Tidskriftsartikel (refereegranskat)abstract
- Oil palm empty fruit bunch (OPEFB) is a potential raw material for production of lignocellulosic bioethanol. The OPEFB was pretreated with 8% sodium hydroxide (NaOH) solution at 100°C for 10 to 90 min. Enzymatic digestion was carried out using cellulase and β-glucosidase at 45°C for 24 h. It was then inoculated with Mucor indicus spores suspension and fermented under anaerobic conditions at 37°C for 96 h. Sodium hydroxide pretreatment effectively removed 51–57% of lignin in the OPEFB and also its hemicellulose (40–84%). The highest glucan digestibility (0.75 g/g theoretical glucose) was achieved in 40-min NaOH pretreatment. Fermentation by M. indicus resulted in 68.4% of the theoretical ethanol yield, while glycerol (16.2–83.2 mg/g), succinic acid (0–0.4 mg/g), and acetic acid (0–0.9 mg/g) were its by-products. According to these results, 11.75 million tons of dry OPEFB in Indonesia can be converted into 1.5 billion liters of ethanol per year.
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| 35. |
- Ferreira, Jorge A., et al.
(författare)
-
Spent sulphite liquor for cultivation of an edible Rhizopus sp.
- 2012
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Ingår i: BioResources. - : North Carolina State University: College of Natural Resources. - 1930-2126. ; 7:1, s. 173-188
-
Tidskriftsartikel (refereegranskat)abstract
- Spent sulphite liquor, the major byproduct from the sulphite pulp production process, was diluted to 50% and used for production of an edible zygomycete Rhizopus sp. The focus was on production, yield, and composition of the fungal biomass composition. The fungus grew well at 20 to 40°C, but 32°C was found to be preferable compared to 20 and 40°C in terms of biomass production and yield (maximum of 0.16 g/g sugars), protein content (0.50-0.60 g/g), alkali-insoluble material (AIM) (ca 0.15 g/g), and glucosamine content (up to 0.30 g/g of AIM). During cultivation in a pilot airlift bioreactor, the yield increased as aeration was raised from 0.15 to 1.0 vvm, indicating a high demand for oxygen. After cultivation at 1.0 vvm for 84 h, high yield and production of biomass (up to 0.34 g/g sugars), protein (0.30-0.50 g/g), lipids (0.02-0.07 g/g), AIM (0.16-0.28 g/g), and glucosamine (0.22-0.32 g/g AIM) were obtained. The fungal biomass produced from spent sulphite liquor is presently being tested as a replacement for fishmeal in feed for fish aquaculture and seems to be a potential source of nutrients and for production of glucosamine.
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| 36. |
- Forgács, Gergely, et al.
(författare)
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Methane production from feather waste pretreated with Ca(OH)2: Process development and economical analysis
- 2014
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Ingår i: Waste and Biomass Valorization. - : Springer Netherlands. - 1877-2641 .- 1877-265X. ; 5:1, s. 65-73
-
Tidskriftsartikel (refereegranskat)abstract
- This study investigated the industrial application of feather waste as a substrate for anaerobic digestion. Feather was pretreated with 0–0.2 Ca(OH)2 g/g TSfeather (total solids of feathers) for 30–120 min at 100–120 °C, in order to increase the digestibility, and to enhance the methane yield in a subsequent digestion at 55 °C. Based on the results of the batch digestion, an industrial process was developed, which can achieve 0.40 Nm3/kg VSfeather (volatile solids of feathers) methane yield from the pretreated feathers, while it fulfills the animal by-product hygenization requirements as well. This base case of the industrial pretreatment process was designed using SuperPro Designer® for utilizing 2,500 tons of feathers per year, which is the waste stream from an average slaughterhouse with a capacity of 60,000 broilers per day. The production cost of the methane is estimated to be 0.475 EUR/Nm3, while the investments on the pretreatment unit requires 0.97 million EUR as total capital investment, and 0.25 million EUR/year for operating cost. However, the process is sensitive to the plant capacity. Changing the plant capacity from 625 to 10,000 tons of feather per year, results in reducing the biogas production cost from 1.177 to 0.203 EUR/Nm3. In addition, sensitivity analysis was performed on the base case to investigate the effect of the value of the incoming feather on the overall process profitability. The results showed that the proposed investment could be considered as being financially viable in the case of production of upgraded biomethane even without the current gate fee system.
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| 37. |
- Gaur, V. K., et al.
(författare)
-
Production of biosurfactants from agro-industrial waste and waste cooking oil in a circular bioeconomy : An overview
- 2022
-
Ingår i: Bioresource Technology. - : Elsevier Ltd. - 0960-8524 .- 1873-2976. ; 343
-
Forskningsöversikt (refereegranskat)abstract
- Waste generation is becoming a global concern owing to its adverse effects on environment and human health. The utilization of waste as a feedstock for production of value-added products has opened new avenues contributing to environmental sustainability. Microorganisms have been employed for production of biosurfactants as secondary metabolites by utilizing waste streams. Utilization of waste as a substrate significantly reduces the cost of overall process. Biosurfactant(s) derived from these processes can be utilized in environmental and different industrial sectors. This review focuses on global market of biosurfactants followed by discussion on production of biosurfactants from waste streams such as agro-industrial waste and waste cooking oil. The need for waste stream derived circular bioeconomy and scale up of biosurfactant production have been narrated with applications of biosurfactants in environment and industrial sectors. Road blocks and future directions for research have also been discussed. © 2021 Elsevier Ltd
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| 38. |
- Gaur, V K, et al.
(författare)
-
Sustainable strategies for combating hydrocarbon pollution : Special emphasis on mobil oil bioremediation
- 2022
-
Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 832
-
Tidskriftsartikel (refereegranskat)abstract
- The global rise in industrialization and vehicularization has led to the increasing trend in the use of different crude oil types. Among these mobil oil has major application in automobiles and different machines. The combustion of mobil oil renders a non-usable form that ultimately enters the environment thereby causing problems to environmental health. The aliphatic and aromatic hydrocarbon fraction of mobil oil has serious human and environmental health hazards. These components upon interaction with soil affect its fertility and microbial diversity. The recent advancement in the omics approach viz. metagenomics, metatranscriptomics and metaproteomics has led to increased efficiency for the use of microbial based remediation strategy. Additionally, the use of biosurfactants further aids in increasing the bioavailability and thus biodegradation of crude oil constituents. The combination of more than one approach could serve as an effective tool for efficient reduction of oil contamination from diverse ecosystems. To the best of our knowledge only a few publications on mobil oil have been published in the last decade. This systematic review could be extremely useful in designing a micro-bioremediation strategy for aquatic and terrestrial ecosystems contaminated with mobil oil or petroleum hydrocarbons that is both efficient and feasible. The state-of-art information and future research
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| 39. |
- Jafari, V., et al.
(författare)
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Construction and demolition lignocellulosic wastes to bioethanol
- 2011
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Ingår i: Renewable Energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; 36:11, s. 2771-2775
-
Tidskriftsartikel (refereegranskat)abstract
- This work deals with conversion of four construction and demolition (C&D) lignocellulosic wastes including OSB, chipboard, plywood, and wallpaper to ethanol by separate enzymatic hydrolysis and fermentation (SHF). Similar to other lignocelluloses, the wastes were resistant to the enzymatic hydrolysis, in which only up to 7% of their cellulose was hydrolyzed. Therefore, the lignocellulosic wastes were treated with phosphoric acid, sodium hydroxide, or N-methylmorpholine-N-oxide (NMMO), which resulted in improving the subsequent enzymatic hydrolysis to 38.2-94.6% of the theoretical yield. The best performance was obtained after pretreatment by concentrated phosphoric acid, followed by NMMO. The pretreated and hydrolyzed C&D wastes were then successfully fermented by baker's yeast to ethanol with 70.5-84.2% of the theoretical yields. The results indicate the possibility of producing 160 ml ethanol from each kg of the C&D wastes at the best conditions.
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| 40. |
- Jeihanipour, Azam, 1982, et al.
(författare)
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Enhancement of solubilization rate of cellulose in anaerobic digestion and its drawbacks
- 2011
-
Ingår i: Process Biochemistry. - : Elsevier BV. - 1359-5113 .- 1873-3298. ; 46:7, s. 1509-1514
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Tidskriftsartikel (refereegranskat)abstract
- Hydrolysis is widely acknowledged as the rate-limiting step in anaerobic digestion of solid cellulose to biogas, and pretreatment is generally considered to facilitate the process. However, few studies have investigated how such pretreatment may affect the rest of this complex process. The present study compared the solubilization rate in anaerobic digestion of cotton linter (high crystalline cellulose), with that of regenerated cellulose (amorphous cellulose), using pretreatment with NMMO. Batch digestions were performed, with the initial cellulose concentrations ranging between 5 and 40 g/l, and during 30 days of incubation, biogas and VFAs production as well as pH and COD changes were measured. The lag time before digestion started was longer for the high crystalline cellulose than for the amorphous one. The maximum solubilization ratesof treated cellulose were 842 and 517 mg sCOD/g cCOD/day at the initial cellulose concentration of 5 and 30 g/l respectively, while the solubilization rate of untreated cellulose never exceeded 417 mg sCOD/g cCOD/day. The difference between the two cellulose types was a direct result of the high rate of hydrolysis inhibiting the acetogenesis/methanogenesis microorganisms, a drawback to the rest of the process.
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| 41. |
- Jeihanipour, Azam, et al.
(författare)
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Ethanol production from cotton-based waste textiles
- 2009
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Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 100:2, s. 1007-1010
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Tidskriftsartikel (refereegranskat)abstract
- Ethanol production from cotton linter and waste of blue jeans textiles was investigated. In the best case, alkali pretreatment followed by enzymatic hydrolysis resulted in almost complete conversion of the cotton and jeans to glucose, which was then fermented by Saccharomyces cerevisiae to ethanol. If no pretreatment applied, hydrolyses of the textiles by cellulase and P-glucosidase for 24 h followed by simultaneous saccharification and fermentation (SSF) in 4 days, resulted in 0.140-0.145 g ethanol/g textiles, which was 25-26% of the corresponding theoretical yield. A pretreatment with concentrated phosphoric acid prior to the hydrolysis improved ethanol production from the textiles up to 66% of the theoretical yield. However, the best results obtained from alkali pretreatment of the materials by NaOH. The alkaline pretreatment of cotton fibers were carried out with 0-20% NaOH at 0 degrees C, 23 degrees C and 100 degrees C, followed by enzymatic hydrolysis up to 4 days. In general, higher concentration of NaOH resulted in a better yield of the hydrolysis, whereas temperature had a reverse effect and better results were obtained at lower temperature. The best conditions for the alkali pretreatment of the cotton were obtained in this study at 12% NaOH and 0 degrees C and 3 h. In this condition, the materials with 3% solid content were enzymatically hydrolyzed at 85.1% of the theoretical yield in 24 h and 99.1% in 4 days. The alkali pretreatment of the waste textiles at these conditions and subsequent SSF resulted in 0.48 g ethanol/g pretreated textiles used. (c) 2008 Elsevier Ltd. All rights reserved.
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| 42. |
- Karimi, Keikhosro, et al.
(författare)
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Fed-batch cultivation of Mucor indicus in dilute-acid lignocellulosic hydrolyzate for ethanol production
- 2005
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Ingår i: BIOTECHNOLOGY LETTERS. - : Springer Science and Business Media LLC. - 0141-5492 .- 1573-6776. ; 27:18
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Tidskriftsartikel (refereegranskat)abstract
- Mucor indicus fermented dilute-acid lignocellulosic hydrolyzates to ethanol in fed-batch cultivation with complete hexose utilization and partial uptake of xylose. The fungus was tolerant to the inhibitors present in the hydrolyzates. It grew in media containing furfural (1 g/l), hydroxymethylfurfural (1 g/l), vanillin (1 g/l), or acetic acid (7 g/l), but did not germinate directly in the hydrolyzate. However, with fed-batch methodology, after initial growth of M. indicus in 500 ml enzymatic wheat hydrolyzate, lignocellulosic hydrolyzate was fermented with feeding rates 55 and 100 ml/h. The fungus consumed more than 46% of the initial xylose, while less than half of this xylose was excreted in the form of xylitol. The ethanol yield was 0.43 g/g total consumed sugar, and reached the maximum concentration of 19.6 g ethanol/l at the end of feeding phase. Filamentous growth, which is regarded as the main obstacle to large-scale cultivation of M. indicus, was avoided in the fed-batch experiments.
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| 43. |
- Khodaverdi, M., et al.
(författare)
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Kinetic modeling of rapid enzymatic hydrolysis of crystalline cellulose after pretreatment by NMMO
- 2012
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Ingår i: Journal of Industrial Microbiology and Biotechnology. - : Oxford University Press (OUP). - 1367-5435 .- 1476-5535 .- 0973-7510. ; 39:3, s. 429-438
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Tidskriftsartikel (refereegranskat)abstract
- Pretreatment of cellulose with an industrial cellulosic solvent, N-methylmorpholine-N-oxide, showed promising results in increasing the rate of subsequent enzymatic hydrolysis. Cotton linter was used as high crystalline cellulose. After the pretreatment, the cellulose was almost completely hydrolyzed in less than 12 h, using low enzyme loading (15 FPU/g cellulose). The pretreatment significantly decreased the total crystallinity of cellulose from 7.1 to 3.3, and drastically increased the enzyme adsorption capacity of cellulose by approximately 42 times. A semi-mechanistic model was used to describe the relationship between the cellulose concentration and the enzyme loading. In this model, two reactions for heterogeneous reaction of cellulose to glucose and cellobiose, and a homogenous reaction for cellobiose conversion to glucose was incorporated. The Langmuir model was applied to model the adsorption of cellulase onto the treated cellulose. The competitive inhibition was also considered for the effects of sugar inhibition on the rate of enzymatic hydrolysis. The kinetic parameters of the model were estimated by experimental results and evaluated.
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| 44. |
- Koul, Y, et al.
(författare)
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Microbial electrolysis : a promising approach for treatment and resource recovery from industrial wastewater
- 2022
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Ingår i: Bioengineered. - : Informa UK Limited. - 2165-5979 .- 2165-5987. ; 13:4, s. 8115-8134
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Tidskriftsartikel (refereegranskat)abstract
- Wastewater is one of the most common by-products of almost every industrial process. Treatment of wastewater alone, before disposal, necessitates an excess of energy. Environmental concerns over the use of fossil fuels as a source of energy have prompted a surge in demand for alternative energy sources and the development of sophisticated procedures to extract energy from unconventional sources. Treatment of municipal and industrial wastewater alone accounts for about 3% of global electricity use while the amount of energy embedded in the waste is at least 2-4 times greater than the energy required to treat the same effluent. The microbial electrolysis cell (MEC) is one of the most efficient technologies for waste-to-product conversion that uses electrochemically active bacteria to convert organic matter into hydrogen or a variety of by-products without polluting the environment. This paper highlights existing obstacles and future potential in the integration of Microbial Electrolysis Cell with other processes like anaerobic digestion coupled system, anaerobic membrane bioreactor and thermoelectric micro converter.
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| 45. |
- Lennartsson, Patrik, et al.
(författare)
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A pilot study on lignocelluloses to ethanol and fish feed using NMMO pretreatment and cultivation with Zygomycetes in an airlift reactor
- 2011
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Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 102:6, s. 4425-4432
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Tidskriftsartikel (refereegranskat)abstract
- A complete process for the production of bioethanol and fungal biomass from spruce and birch was investigated. The process included milling, pretreatment with N-methylmorpholine-N-oxide (NMMO), washing of the pretreated wood, enzymatic hydrolysis, and cultivation of the zygomycetes fungi Mucor indicus. Investigated factors included wood chip size (0.5-16 mm), pretreatment time (1-5 h), and scale of the process from bench-scale to 2 m high airlift reactor. Best hydrolysis yields were achieved from wood chips below 2 mm after 5 h of pretreatment. Ethanol yields (mg/g wood) of 195 and 128 for spruce, and 175 and 136 for birch were achieved from bench-scale and airlift, respectively. Fungal biomass yields (mg/g wood) of 103 and 70 for spruce, and 86 and 66 for birch from bench scale and airlift respectively were simultaneously achieved. NMMO pretreatment and cultivation with M. indicus appear to be a good alternative for ethanol production from birch and spruce.
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| 46. |
- Millati, Ria, 1972, et al.
(författare)
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Ethanol from Oil Palm Empty Fruit Bunch via Dilute-Acid Hydrolysis and Fermentation by Mucor indicus and Saccharomyces cerevisiae
- 2011
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Ingår i: Agricultural Journal. - : Medwell Journals. - 1994-4616 .- 1816-9155. ; 6:2, s. 54-59
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Tidskriftsartikel (refereegranskat)abstract
- Oil Palm Empty Fruit Bunch (OPEFB) was hydrolyzed in a one-stage hydrolysis using dilute-sulfuric acid (0.2, 0.8%) at 170-230°C with a holding time of 5 and 15 min. The maximum yield of xylose was 135.94 g kg-1 OPEFB, obtained at 0.8% acid, 190°C and 5 min. The maximum yield of glucose was 62.70 g kg-1 OPEFB, obtained at 0.8% acid, 210°C and 5 min. Based on these results, two-stage hydrolysis was performed to produce hydrolyzates for the fermentation process. Hydrolyzate from the first stage was fermented by Mucor indicus while the hydrolyzate from the second stage was fermented by Saccharomyces cerevisiae. The corresponding ethanol yields were 0.45 and 0.46 g ethanol g-1 sugar consumed.
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| 47. |
- Purwadi, Ronny, et al.
(författare)
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The performance of serial bioreactors in rapid continuous production of ethanol from dilute-acid hydrolyzates using immobilized cells
- 2008
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Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 99:7, s. 2226-2233
-
Tidskriftsartikel (refereegranskat)abstract
- The performance of single, and series of, continuous stirred-tank (CSTBR) and fluidized-bed bioreactor (FBBR) in anaerobic continuous cultivation of glucose in defined media and dilute-acid hydrolyzates at dilution rates 0.22, 0.43, 0.65 and 0.86 h -1 using immobilized Saccharomyces cerevisiae CBS 8066, was investigated. While the single CSTBR and FBBR could not take up more than 77% and 92% of glucose in a defined medium at dilution rate 0.86 h -1 , addition of the second bioreactor decreased the residual glucose to less than 1.1% of the incoming sugar. A similar trend was obtained in cultivation of dilute-acid hydrolyzates. A CSTBR could take up 75% and 54% of the initial fermentable sugars at dilution rates 0.43 and 0.86 h -1 , while the addition of the FBBR improved the assimilation of the sugars to 100% and 86%, respectively. The ethanol yields from the hydrolyzate were between 0.41 and 0.48 g/g in all the experiments. The specific and volumetric ethanol productivities were 1.13 g/g h and 5.98 g/L h for the single bioreactor and 0.98 g/g h and 5.49 g/L h for the serial bioreactor at the highest dilution rate, respectively. Glycerol was the only important by-product in terms of concentration, and yielded 0.05-0.07 g/g from the hydrolyzate. From the initial 3.98 g/L acetic acid present in the hydrolyzate, 0.1-0.8 g/L was assimilated by the cells. The yeast cells were accumulated close to the surface of the beads. While the cells had a dry-weight concentration of 129 g/L close to the surface of the beads, the concentration in the core was only 13 g/L. © 2007 Elsevier Ltd. All rights reserved.
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| 48. |
- Talebnia Rowshan, Farid, 1974, et al.
(författare)
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Physiological and morphological study of encapsulated Saccharomyces cerevisiae
- 2007
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Ingår i: Enzyme and Microbial Technology. - : Elsevier BV. - 0141-0229 .- 1879-0909. ; 41:6-7, s. 683-688
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Tidskriftsartikel (refereegranskat)abstract
- The impact of encapsulation on the anaerobic growth pattern of S. cerevisiae CBS 8066 in a defined synthetic medium over 20 consecutive batch cultivations was investigated. In this period, the ethanol yield increased from 0.43 to 0.46 g/g, while the biomass and glycerol yields decreased by 5 8 and 23%, respectively. The growth rate of the encapsulated cells in the first batch was 0.13 h(-1), but decreased gradually to 0.01 h(-1) within the 20 sequential batch cultivations. Total RNA content of these yeast cells decreased by 39% from 90.3 to 55 mg/g, while the total protein content decreased by 24% from 460 to 350 mg/g. On the other hand, the stored carbohydrates, that is, glycogen and trehalose content, increased by factors of 4.5 and 4 within 20 batch cultivations, respectively. Higher biomass concentrations inside capsules led to a lower glucose diffusion rate through the membrane, and volumetric mass transfer coefficient for glucose was drastically decreased from 6.28 to 1.24 (cm(3)/min) by continuing the experiments. Most of the encapsulated yeast existed in the form of single and non-budding cells after long-term application. (C) 2007 Elsevier Inc. All rights reserved.
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| 49. |
- Westman, Johan, 1983, et al.
(författare)
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Effects of encapsulation of microorganisms on product formation during microbial fermentations
- 2012
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Ingår i: Applied Microbiology and Biotechnology. - : Springer Science and Business Media LLC. - 1432-0614 .- 0175-7598. ; 96:6, s. 1441-1454
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Forskningsöversikt (refereegranskat)abstract
- This paper reviews the latest developments in microbial products by encapsulated microorganisms in a liquid core surrounded by natural or synthetic membranes. Cells can be encapsulated in one or several steps using liquid droplet formation, pregel dissolving, coacervation, and interfacial polymerization. The use of encapsulated yeast and bacteria for fermentative production of ethanol, lactic acid, biogas, l-phenylacetylcarbinol, 1,3-propanediol, and riboflavin has been investigated. Encapsulated cells have furthermore been used for the biocatalytic conversion of chemicals. Fermentation, using encapsulated cells, offers various advantages compared to traditional cultivations, e.g., higher cell density, faster fermentation, improved tolerance of the cells to toxic media and high temperatures, and selective exclusion of toxic hydrophobic substances. However, mass transfer through the capsule membrane as well as the robustness of the capsules still challenge the utilization of encapsulated cells. The history and the current state of applying microbial encapsulation for production processes, along with the benefits and drawbacks concerning productivity and general physiology of the encapsulated cells, are discussed.
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| 50. |
- Westman, Johan, 1983, et al.
(författare)
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Encapsulation-Induced Stress Helps Saccharomyces cerevisiae Resist Convertible Lignocellulose Derived Inhibitors
- 2012
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Ingår i: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 13:9, s. 11881-11894
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Tidskriftsartikel (refereegranskat)abstract
- The ability of macroencapsulated Saccharomyces cerevisiae CBS8066 to withstand readily and not readily in situ convertible lignocellulose-derived inhibitors was investigated in anaerobic batch cultivations. It was shown that encapsulation increased the tolerance against readily convertible furan aldehyde inhibitors and to dilute acid spruce hydrolysate, but not to organic acid inhibitors that cannot be metabolized anaerobically. Gene expression analysis showed that the protective effect arising from the encapsulation is evident also on the transcriptome level, as the expression of the stress-related genes YAP1, ATR1 and FLR1 was induced upon encapsulation. The transcript levels were increased due to encapsulation already in the medium without added inhibitors, indicating that the cells sensed low stress level arising from the encapsulation itself. We present a model, where the stress response is induced by nutrient limitation, that this helps the cells to cope with the increased stress added by a toxic medium, and that superficial cells in the capsules degrade convertible inhibitors, alleviating the inhibition for the cells deeper in the capsule.
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