| 1. |
- Abedinifar, S., et al.
(författare)
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Ethanol production by Mucor indicus and Rhizopus oryzae from rice straw by separate hydrolysis and fermentation
- 2009
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Ingår i: Biomass and Bioenergy. - : Elsevier BV. - 0961-9534 .- 1873-2909. ; 33:5, s. 828-833
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Tidskriftsartikel (refereegranskat)abstract
- Rice straw was successfully converted to ethanol by separate enzymatic hydrolysis and fermentation by Mucor indicus, Rhizopus oryzae, and Saccharomyces cerevisiae. The hydrolysis temperature and pH of commercial cellulase and β-glucosidase enzymes were first investigated and their best performance obtained at 45 °C and pH 5.0. The pretreatment of the straw with dilute-acid hydrolysis resulted in 0.72 g g-1 sugar yield during 48 h enzymatic hydrolysis, which was higher than steam-pretreated (0.60 g g-1) and untreated straw (0.46 g g-1). Furthermore, increasing the concentration of the dilute-acid pretreated straw from 20 to 50 and 100 g L-1 resulted in 13% and 16% lower sugar yield, respectively. Anaerobic cultivation of the hydrolyzates with M. indicus resulted in 0.36-0.43 g g-1 ethanol, 0.11-0.17 g g-1 biomass, and 0.04-0.06 g g-1 glycerol, which is comparable with the corresponding yields by S. cerevisiae (0.37-0.45 g g-1 ethanol, 0.04-0.10 g g-1 biomass and 0.05-0.07 glycerol). These two fungi produced no other major metabolite from the straw and completed the cultivation in less than 25 h. However, R. oryzae produced lactic acid as the major by-product with yield of 0.05-0.09 g g-1. This fungus had ethanol, biomass and glycerol yields of 0.33-0.41, 0.06-0.12, and 0.03-0.04 g g-1, respectively.
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| 2. |
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| 3. |
- Lennartsson, Patrik R, 1983, et al.
(författare)
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Effects of different growth forms of Mucor indicus on cultivation on dilute-acid lignocellulosic hydrolyzate, inhibitor tolerance, and cell wall composition
- 2009
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Ingår i: Journal of Biotechnology. - : Elsevier BV. - 0168-1656 .- 1873-4863. ; 143:4, s. 255-261
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Tidskriftsartikel (refereegranskat)abstract
- The dimorphic fungus Mucor indicus was grown in different forms classified as purely filamentous, mostly filamentous, mostly yeast-like and purely yeast-like, and the relationship between morphology and metabolite production, inhibitor tolerance and the cell wall composition was investigated. Low concentrations of spores in the inoculum with subsequent aeration promoted filamentous growth, whereas higher spore concentrations and anaerobic conditions promoted yeast-like growth. Ethanol was the main metabolite with glycerol next under all conditions tested. The yields of ethanol from glucose were between 0.39 and 0.42 g g(-1) with productivities of 3.2-5.0 g l(-1) h(-1). The ethanol productivity of mostly filamentous cells was increased from 3.9 to 5.0 g l(-1) h(-1) by the presence of oxygen, whereas aeration of purely yeast-like cells showed no such effect. All growth forms were able to tolerate 4.6 g l(-1) furfural and 10 g l(-1) acetic acid and assimilate the sugars, although with different consumption rates. The cell wall content of the fungus measured as alkali insoluble materials (AIM) of the purely yeast-like cells was 26% of the biomass, compared to 8% of the pure filaments. However, the chitosan concentration of the filaments was 29% of the AIM, compared to 6% of the yeast-like cells.
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| 4. |
- Satari, Behzad, et al.
(författare)
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Co-Production of Fungal Biomass Derived Constituents and Ethanol from Citrus Wastes Free Sugars without Auxiliary Nutrients in Airlift Bioreactor
- 2016
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Ingår i: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 17:3
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Tidskriftsartikel (refereegranskat)abstract
- The potential of two zygomycetes fungi, Mucor indicus and Rhizopus oryzae, in assimilating citrus waste free sugars (CWFS) and producing fungal chitosan, oil, and protein as well as ethanol was investigated. Extraction of free sugars from citrus waste can reduce its environmental impact by decreasing the possibility of wild microorganisms growth and formation of bad odors, a typical problem facing the citrus industries. A total sugar concentration of 25.1 g/L was obtained by water extraction of citrus waste at room temperature, used for fungal cultivation in shake flasks and airlift bioreactor with no additional nutrients. In shake flasks cultivations, the fungi were only able to assimilate glucose, while fructose remained almost intact. In contrast, the cultivation of M. indicus and R. oryzae in the four-liter airlift bioreactor resulted in the consumption of almost all sugars and production of 250 and 280 g fungal biomass per kg of consumed sugar, respectively. These biomasses correspondingly contained 40% and 51% protein and 9.8% and 4.4% oil. Furthermore, the fungal cell walls, obtained after removing the alkali soluble fraction of the fungi, contained 0.61 and 0.69 g chitin and chitosan per g of cell wall for M. indicus and R. oryzae, respectively. Moreover, the maximum ethanol yield of 36% and 18% was obtained from M. indicus and R. oryzae, respectively. Furthermore, that M. indicus grew as clump mycelia in the airlift bioreactor, while R. oryzae formed spherical suspended pellets, is a promising feature towards industrialization of the process.[on SciFinder (R)]
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| 5. |
- Shafiei, Marzieh, et al.
(författare)
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Palm Date Fibers : Analysis and Enzymatic Hydrolysis
- 2010
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Ingår i: International Journal of Molecular Sciences. - : Molecular Diversity Preservation International (MDPI) AG.. - 1661-6596 .- 1422-0067. ; 11:11, s. 4285-4296
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Tidskriftsartikel (refereegranskat)abstract
- Waste palm dates were subjected to analysis for composition and enzymatic hydrolysis of their flesh fibers. The fruit contained 32% glucose and 30% fructose, while the water-insoluble fibers of its flesh consisted of 49.9% lignin and 20.9% polysaccharides. Water-insoluble fibers were settled to 55% of its initial volume in 12 h. The presence of skin and flesh colloidal fibers results in high viscosity and clogging problems during industrial processes. The settling velocity of the fibers was improved by enzymatic hydrolysis. Hydrolysis resulted in 84.3% conversion of the cellulosic part of the fibers as well as reducing the settling time to 10 minutes and the final settled volume to 4% of the initial volume. It implies easier separation of the fibers and facilitates fermentation processes in the corresponding industries. Two kinds of high- and low-lignin fibers were identified from the water-insoluble fibers. The high-lignin fibers (75% lignin) settled easily, while the low-lignin fibers (41.4% lignin) formed a slurry suspension which settled very slowly. The hydrophilicity of these low-lignin fibers is the major challenge of the industrial processes.
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| 6. |
- Molaverdi, Maryam, et al.
(författare)
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High efficient ethanol production from corn stover by modified mild alkaline pretreatment
- 2021
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Ingår i: Renewable Energy. - : Elsevier BV. - 0960-1481. ; 170, s. 714-723
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Tidskriftsartikel (refereegranskat)abstract
- Sodium carbonate pretreatment, an environmentally-friendly and efficient pretreatment, was used to improve solid-state ethanol production from corn stover (CS). To further enhance ethanol yield from the pretreated CS, especially at low enzyme loadings, a combined pretreatment, including steam and sodium carbonate pretreatments, was developed. The removal/modification of lignin by sodium carbonate pretreatment (at 100 °C for 3 h) helped to obtain high ethanol titer at high solids and low enzymes loadings. The maximum ethanol concentration was about 44 g/L, obtained after 72 h simultaneous saccharification and fermentation (SSF) of CS pretreated with sodium carbonate without mixing and prehydrolysis at 30% solid and 15 FPU/g enzyme loadings. Applying prehydrolysis and increasing the SSF time to 120 h improved ethanol concentration to 59 and 67 g/L, respectively. Steam pretreatment at 190 °C for 10 min before sodium carbonate pretreatment led to 76% increase in ethanol concentration. At the enzyme loading of only 5 FPU/g substrate, the modified pretreatment increased the ethanol concentration from 24 g/L to 41 g/L, compared with that of sodium carbonate pretreatment. The results showed that hemicellulose removal and delignification by steam and sodium carbonate pretreatment, respectively, considerably improved ethanol concentration at high solids and low enzyme loadings.
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| 7. |
- Molaverdi, Maryam, et al.
(författare)
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High titer ethanol production from rice straw via solid-state simultaneous saccharification and fermentation by Mucor indicus at low enzyme loading
- 2019
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Ingår i: Energy Conversion and Management. - : Elsevier BV. - 0196-8904. ; 182, s. 520-529
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Tidskriftsartikel (refereegranskat)abstract
- High titer ethanol production from rice straw using Mucor indicus fungus was investigated through the solid-state simultaneous saccharification and fermentation (SSSF) process. The straw was pretreated with 0.5 M sodium carbonate solution for 3, 5, and 10 h to improve the efficiency of the process. Effects of the pretreatment on the composition, structural morphology, cellulose crystallinity, swelling capacity, and buffering capacity of the straw were studied. Moreover, the effects of SSSF reaction time, enzyme loading, and solid loading on glucose and ethanol production were investigated. Additionally, the nutritional value of the residue from the SSSF process, as an animal feedstock, was determined in terms of lipid and protein contents. The highest total sugar concentration was 89.2 g/L, obtained from the straw pretreated for 10 h after hydrolysis with 10 FPU/g straw at 15% (w/w) solid loading. Total sugars concentration was not significantly improved by increasing the pretreatment time at low enzyme loadings, whereas it was significantly improved at high enzyme loadings. The highest ethanol concentration and SSSF yield were 99.4 g/L and 89.5% (71.8% based on the raw material), achieved from the straw pretreated for 10 h through the 72-h SSSF at 30% and 15% solid loading, respectively, using 20 FPU/g straw. The low enzyme loadings of 2.5 and 5 FPU/g straw yielded ethanol with concentrations as high as 66.3 and 90.9 g/L, respectively, after 120-h fermentation at 30% solid loading from the straw pretreated for 5 h.
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