| 1. |
- Badshah, Malik, et al.
(författare)
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Anaerobic treatment of methanol condensate from pulp mill compared with anaerobic treatment of methanol using mesophilic UASB reactors.
- 2012
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Ingår i: Bioresource Technology. - : Elsevier BV. - 1873-2976 .- 0960-8524. ; 125C, s. 318-327
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Tidskriftsartikel (refereegranskat)abstract
- The feasibility of anaerobic treatment of methanol condensate from pulp and paper mill in UASB reactor was investigated and compared with the anaerobic treatment of methanol. The UASB reactor treating methanol condensate was operated for 480days with minimum problems of overload. COD removal from methanol condensate and methanol under normal operating conditions ranged from 84-86% to 86-98%, respectively. Under optimal conditions (OLR=5.0gCODL(-1)day(-1), COD(influent)=11.40gL(-1)) a methane yield of 0.29 NL CH(4) per g COD(removed) (at standard temperature and pressure) was achieved during the treatment of methanol condensate. The recovery time of the microorganisms after several overloads was decreasing each time probably due to the adaptation to methanol condensate. These findings indicate that methanol condensate can be efficiently treated in a UASB reactor with the benefit of biogas production. As a bonus effect of the treatment, much of the smell of the feed was eliminated.
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| 2. |
- Badshah, Malik
(författare)
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Evaluation of process parameters and treatments of different raw materials for biogas production
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The anaerobic digestion process results in the production of biogas from a large diversity of organic residues, which can be used as an alternate source of energy generation and for waste management. However, the biogas production technology is not exploited efficiently due to the characteristics of raw materials, poor methane yields, process instability, limited raw materials and lack of knowledge about the process. Effects of various parameters and different treatments on the performance and stability of the anaerobic digestion process were investigated in this thesis work. Arrays of substrates were subjected to the biochemical methane potential (BMP) batch assay to evaluate the impact of source of inoculum, inoculum to substrate ratio, characteristics of substrate and presence of toxic chemicals on the methane yield and kinetics of methane production during anaerobic digestion. Biogas production from sugarcane bagasse and pulp mill sludges was studied after different pretreatments. Biogas production from rectified methanol condensate from pulp and paper mill was investigated at different operating conditions. Inoculum was found to be an important factor that affects the anaerobic digestion. Different parameters related to inoculum studied were: source of inoculum, inoculum to substrate ratio and adaptation of inoculum. It was found that inoculum to substrate ratio has impact on the reduction of volatile solids and the rate of methanogenesis during anaerobic digestion. Increasing the inoculum to substrate ratio enhanced the reduction in volatile solids and methane production rate during anaerobic digestion of sodium acetate. The source of inoculum significantly affected the methane production rate but had no marked influence on the ultimate methane yield. Long term exposure of anaerobic consortia to methanol condensate from pulp mill in an upflow anaerobic sludge bed reactor caused adaptation of the microbial consortia to the feed and hence it became more tolerant to toxic material in methanol condensate. The adaptation resulted in an increase in the methane yield and reduced the recovery time after failure of the process. The treatment with diluted acid of sugarcane bagasse followed by enzymatic hydrolysis resulted in the release of considerable amounts of monomeric sugars that afterwards were subjected to anaerobic digestion. These treatments led to significant improvements in yields as compared to when raw sugarcane bagasse was digested. Additionally, higher amount of methane was produced from anaerobic digestion of sugarcane bagasse treated with acid alone compared to when raw sugarcane was subjected to anaerobic digestion but the yields were lower than that of treatment with diluted acid followed by enzymatic hydrolysis. Furaldehydes i.e. furfural and hydroxymethylfurfural at concentrations formed during the pretreatments of lignocellulosic biomass were found to be non-inhibitory and degradable during anaerobic digestion. However, high concentrations of furaldehydes affected the biogas production. The effect of the higher concentration of furaldehydes was evident on biogas production kinetics. The amount and rate of biogas production from a substrate is highly dependent on the composition and characteristics of the substrate. To compare the extent of degradability among different substrates, the methane yield based on the COD basis provides a better option than the methane yield based on volatile solids.
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| 3. |
- Badshah, Malik, et al.
(författare)
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Use of an Automatic Methane Potential Test System for evaluating the biomethane potential of sugarcane bagasse after different treatments.
- 2012
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Ingår i: Bioresource Technology. - : Elsevier BV. - 1873-2976 .- 0960-8524. ; 114, s. 262-269
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Tidskriftsartikel (refereegranskat)abstract
- A multi-channel analyzer was used to evaluate biogas potential of sugarcane bagasse (SCB). The Automatic Methane Potential Test System contained fifteen parallel reactors and the same number of gas flow meters attached to the acquisition system. The set of reactors - gas flow meters gave reproducible results during anaerobic digestion of chemically defined carbon source and the units were used to evaluate the biomethane potential of SCB after different pretreatments, such as treatment with water, acid, acid followed by enzymatic treatment and acid followed by treatment with inactive enzymes. Combined pretreatment with 2% sulphuric acid and enzymatic hydrolysis (3.5% enzymes) resulted in conversion of 79% to monomeric sugars present in SCB. SCB treated with acid followed by enzymatic hydrolysis achieved the methane yield of 200NL per kg VS(added). Enzymatic saccharification of acid pretreated SCB resulted in increase of methane yield by 16±5% compared to that from acid treated SCB.
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| 4. |
- Crespo, Carla, et al.
(författare)
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Ethanol production by continuous fermentation of d-(+)-cellobiose, d-(+)-xylose and sugarcane bagasse hydrolysate using the thermoanaerobe Caloramator boliviensis.
- 2012
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Ingår i: Bioresource Technology. - : Elsevier BV. - 1873-2976 .- 0960-8524. ; 103:1, s. 186-191
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Tidskriftsartikel (refereegranskat)abstract
- The recently isolated anaerobic bacterium Caloramator boliviensis with an optimum growth temperature of 60°C can efficiently convert hexoses and pentoses into ethanol. When fermentations of pure sugars and a pentose-rich sugarcane bagasse hydrolysate were carried out in a packed bed reactor with immobilized cells of C. boliviensis, more than 98% of substrates were converted. Ethanol yields of 0.40-0.46g/g of sugar were obtained when sugarcane bagasse hydrolysate was fermented. These features reveal interesting properties of C. boliviensis in producing ethanol from a renewable feedstock.
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| 5. |
- Din, Salah Ud, et al.
(författare)
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The Purification and Characterization of a Cutinase-like Enzyme with Activity on Polyethylene Terephthalate (PET) from a Newly Isolated Bacterium Stenotrophomonas maltophilia PRS8 at a Mesophilic Temperature
- 2023
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Ingår i: Applied Sciences (Switzerland). - : MDPI AG. - 2076-3417. ; 13:6
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Tidskriftsartikel (refereegranskat)abstract
- A polyethylene terephthalate (PET)-degrading bacterium identified as Stenotrophomonas maltophilia PRS8 was isolated from the soil of a landfill. The degradation of the PET bottle flakes and the PET prepared as a powder were assessed using live cells, an extracellular medium, or a purified cutinase-like enzyme. These treated polymers were analyzed using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The depolymerization products, identified using HPLC and LC-MS, were terephthalic acid (TPA), mono(2-hydroxyethyl)-TPA (MHET), and bis(2-hydroxyethyl)-TPA (BHET). Several physicochemical factors were optimized for a better cutinase-like enzyme production by using unique single-factor and multi-factor statistical models (the Plackett–Burman design and the central composite design software). The enzyme was purified for homogeneity through column chromatography using Sephadex G-100 resin. The molecular weight of the enzyme was approximately 58 kDa. The specific activity on para nitrophenyl butyrate was estimated at 450.58 U/mg, with a purification of 6.39 times and a yield of 48.64%. The enzyme was stable at various temperatures (30–40 °C) and pH levels (8.0–10.0). The enzyme activity was significantly improved by the surfactants (Triton X-100 and Tween-40), organic solvent (formaldehyde), and metals (NiCl2 and Na2SO4). The extracellular medium containing the cutinase-type enzyme showed a depolymerization yield of the PET powder comparable to that of Idonella skaiensis IsPETase and significantly higher than that of Humicola insolens thermostable HiCut (HiC) cutinase. This study suggests that S. maltophilia PRS8 is able to degrade PET at a mesophilic temperature and could be further explored for the sustainable management of plastic waste.
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| 6. |
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| 7. |
- Moshi, Anselm, et al.
(författare)
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Characterisation and evaluation of a novel feedstock, Manihot glaziovii, Muell. Arg, for production of bioenergy carriers: Bioethanol and biogas.
- 2014
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Ingår i: Bioresource Technology. - : Elsevier BV. - 1873-2976 .- 0960-8524. ; 172, s. 58-67
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to characterise and evaluate a wild inedible cassava species, Manihot glaziovii as feedstock for bioenergy production. Tubers obtained from 3 different areas in Tanzania were characterised and evaluated for bioethanol and biogas production. These bioenergy carriers were produced both separately and sequentially and their energy values evaluated based on these two approaches. Composition analysis demonstrated that M. glaziovii is a suitable feedstock for both bioethanol and biogas production. Starch content ranged from 77% to 81%, structural carbohydrates 3-16%, total crude protein ranged from 2% to 8%. Yeast fermentation achieved ethanol concentration of up to 85g/L at a fermentation efficiency of 89%. The fuel energy of the bioethanol and methane from flour-peels mix ranged from 5 to 13 and 11 to 14MJ/kgVS, respectively. Co-production of bioethanol and biogas in which the peels were added to the fermentation residue prior to anaerobic digestion produced maximum fuel energy yield of (15-23MJ/kgVS).
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| 8. |
- Moshi, Anselm, et al.
(författare)
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High bioethanol titre from Manihot glaziovii through fed-batch simultaneous saccharification and fermentation in Automatic Gas Potential Test System.
- 2014
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Ingår i: Bioresource Technology. - : Elsevier BV. - 1873-2976 .- 0960-8524. ; 156, s. 348-356
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Tidskriftsartikel (refereegranskat)abstract
- A process for the production of high bioethanol titre was established through fed-batch and simultaneous saccharification and fermentation (FB-SSF) of wild, non-edible cassava Manihot glaziovii. FB-SSF allowed fermentation of up to 390g/L of starch-derived glucose achieving high bioethanol concentration of up to 190g/L (24% v/v) with yields of around 94% of the theoretical value. The wild cassava M. glaziovii starch is hydrolysable with a low dosage of amylolytic enzymes (0.1-0.15% v/w, Termamyl® and AMG®). The Automatic Gas Potential Test System (AMPTS) was adapted to yeast ethanol fermentation and demonstrated to be an accurate, reliable and flexible device for studying the kinetics of yeast in SSF and FB-SSF. The bioethanol derived stoichiometrically from the CO2 registered in the AMPTS software correlated positively with samples analysed by HPLC (R(2)=0.99).
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