scholarly journals Enhanced co-generation of cellulosic ethanol and methane with the starch/sugar-rich waste mixtures and Tween 80 in fed-batch mode

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Meishan Fan ◽  
Jun Li ◽  
Guican Bi ◽  
Guangying Ye ◽  
Hongdan Zhang ◽  
...  
Keyword(s):  
Cellulosic Ethanol ◽  
Ethanol Concentration ◽  
Ethanol Yield ◽  
Tween 80 ◽  
Fed Batch ◽  
Mixed Fermentation ◽  
Batch Mode ◽  
Mixture Ratio ◽  
Theoretical Yield ◽  
Solids Loading

Abstract Background The mixed-feedstock fermentation is a promising approach to enhancing the co-generation of cellulosic ethanol and methane from sugarcane bagasse (SCB) and molasses. However, the unmatched supply of the SCB and molasses remains a main obstacle built upon binary feedstock. Here, we propose a cellulose–starch–sugar ternary waste combinatory approach to overcome this bottleneck by integrating the starch-rich waste of Dioscorea composita Hemls. extracted residue (DER) in mixed fermentation. Results The substrates of the pretreated SCB, DER and molasses with varying ratios were conducted at a relatively low solids loading of 12%, and the optimal mixture ratio of 1:0.5:0.5 for the pretreated SCB/DER/molasses was determined by evaluating the ethanol concentration and yield. Nevertheless, it was found that the ethanol yield decreased from 79.19 ± 0.20 to 62.31 ± 0.61% when the solids loading increased from 12 to 44% in batch modes, regardless of the fact that the co-fermentation of three-component feedstock was performed under the optimal condition defined above. Hence, different fermentation processes such as fed-batch and fed-batch + Tween 80 were implemented to further improve the ethanol concentration and yield at higher solids loading ranging between 36 and 44%. The highest ethanol concentration of 91.82 ± 0.86 g/L (69.33 ± 0.46% of theoretical yield) was obtained with fed-batch + Tween 80 mode during the simultaneous saccharification and fermentation at a high solids loading of 44%. Moreover, after the ethanol recovery, the remaining stillage was digested for biomethane production and finally yielded 320.72 ± 6.98 mL/g of volatile solids. Conclusions Integrated DER into the combination of SCB and molasses would be beneficial for ethanol production. The co-generation of bioethanol and biomethane by mixed cellulose–starch–sugar waste turns out to be a sustainable solution to improve the overall efficacy in biorefinery.

scholarly journals Regio- and Stereoselective Fungal Oxyfunctionalisation of Limonenes

2005 ◽  
Vol 60 (5-6) ◽  
pp. 459-466 ◽  
Author(s):  
Rüdiger Kaspera ◽  
Ulrich Krings ◽  
Michael Pescheck ◽  
Dieter Sell ◽  
Jens Schrader ◽  
...  
Keyword(s):  
Optical Purity ◽  
Product Yield ◽  
Careful Selection ◽  
Fed Batch ◽  
Batch Mode ◽  
Theoretical Yield ◽  
Pleurotus Sapidus ◽  
Terminal Oxidation ◽  
By Products ◽  
Selection Of

Selective transformations of limonene by asco- and basidiomycetes were investigated. On the shake flask scale, Penicillium citrinum hydrated R-(+)-limonene to α-terpineol [83% regioselectivity (rs), more than 80 mg 1-1 product yield], and Gongronella butleri catalysed the terminal oxidation to yield perillyl alcohol (60% rs, 16 mg 1-1). On the laboratory bioreactor scale, Penicillium digitatum produced a peak concentration of 506 mg α-terpineol 1-1 in the fed-batch mode, equivalent to a theoretical yield of 67%, and no volatile by-products were found. Fusarium proliferatum transformed R-(+)-limonene enantiospecifically to cis-(+)- carveol (98.6% ee, more than 35 mg 1-1 product yield) and S-(-)-limonene predominantly to trans-(-)-carveol (96.3% ee). Pleurotus sapidus selectively dehydrogenised the accumulating trans-(-)-carveol to the corresponding enantiopure R-(-)-carvone. The results show that a careful selection of strain and bioprocess parameters may improve both the yield and the optical purity of a desired product.

Construction and Evaluation of Recombinant Strains for Ethanol Production from Lignocellulosic Hydrolysate

2011 ◽  
Vol 347-353 ◽  
pp. 48-51 ◽  
Author(s):  
Shao Lan Zou ◽  
Chao Zhang ◽  
Yuan Yuan Ma ◽  
Le You ◽  
Min Hua Zhang
Keyword(s):  
Carbon Source ◽  
Ethanol Production ◽  
Rapid Growth ◽  
Sole Carbon Source ◽  
Ethanol Concentration ◽  
Ethanol Yield ◽  
Corn Straw ◽  
Lignocellulosic Hydrolysate ◽  
Preliminary Results ◽  
Theoretical Yield

The recombinant Z.mobilis CX was constructed. Its ethanol concentration and ethanol yield from 2% xylose at 36 h were 6.73 g/L and 82.3% of theoretical yield, respectively. The recombinant S.cerevisiae YB was constructed and was showed to utilize cellobiose as the sole carbon source for rapid growth and ethanol production. The maximum ethanol concentration 7.493 g/L and ethanol yield 77.4% of theoretical yield from 2% cellobiose were obtained at 24 h. Further, the preliminary results of SSF of pretreated corn straw demonstrated the potential of improving ethanol production and reducing the costs of cellose enzymes used by co-fermentation of CX and YB.

scholarly journals Microwave-assisted hydrotropic pretreatment as a new and highly efficient way to cellulosic ethanol production from maize distillery stillage

2021 ◽  
Author(s):  
Mikulski Dawid ◽  
Kłosowski Grzegorz
Keyword(s):  
Ethanol Production ◽  
Cellulosic Ethanol ◽  
Enzymatic Degradation ◽  
Ethanol Concentration ◽  
Process Conditions ◽  
Fermentation Inhibitors ◽  
Microwave Assisted ◽  
Theoretical Yield ◽  
High Level ◽  
Very High

Abstract Aim of the study was to assess the suitability of the combined use of microwave radiation and sodium cumene sulfonate under optimized process conditions for the preparation of maize stillage biomass as a raw material for the production of cellulosic ethanol. The key parameter guaranteeing a high level of lignin removal from biomass (ca. 44%) was concentration of hydrotrope. Even at high biomass concentration (16% w/v) and a cellulase enzyme dose of about 4 filter-paper units/g, maize stillage biomass subjected to microwave-assisted hydrotropic pretreatment was highly susceptible to enzymatic degradation, which resulted in 80% hydrolysis yield. It is possible to obtain a fermentation medium with a very high glucose concentration (up to 80 g/L), without fermentation inhibitors and, as a consequence, to reach a very high level of sugar conversion to ethanol (concentration above 40 g/L), even as much as 95% of theoretical yield. Microwave hydrotropic treatment with sodium cumene sulfonate is a very effective way to prepare waste maize stillage biomass for the production of cellulosic ethanol. The degradation of the lignocellulose structure by the simultaneous use of microwaves and hydrotropes ensured a high degree of conversion of structural polysaccharides to bioethanol. The method provides a high level of enzymatic degradation of cellulose, leading to a medium with high content of released sugars suitable for bioconversion, which is in line with assumptions of the second-generation ethanol production technology. Key points • Microwave-assisted hydrotropic pretreatment is a new way to cellulosic ethanol production. • Microwave-assisted hydrotropic delignification removes 44% of lignin from biomass. • No fermentation inhibitors are obtained after microwave-assisted hydrotropic pretreatment. • High ethanol concentration (above 40 g/L) and fermentation yield (95% of theoretical yield) from biomass after microwave-assisted hydrotropic pretreatment.

scholarly journals Strategies for Improvement of Lipid Production by Yeast Trichosporon oleaginosus from Lignocellulosic Biomass

2021 ◽  
Vol 7 (11) ◽  
pp. 934
Author(s):  
Marina Grubišić ◽  
Katarina Mihajlovski ◽  
Ana Marija Gruičić ◽  
Sunčica Beluhan ◽  
Božidar Santek ◽  
...  
Keyword(s):  
Lignocellulosic Biomass ◽  
Low Cost ◽  
Lipid Production ◽  
Tween 80 ◽  
Biodiesel Production ◽  
Hydrolysis Rate ◽  
Efficient Production ◽  
Fed Batch ◽  
Batch Mode ◽  
Lipid Yield

Microbial lipids have similar fatty acid composition to plant oils, and therefore, are considered as an alternative feedstock for biodiesel production. Oleaginous yeasts accumulate considerable amounts of lipids intracellularly during growth on low-cost renewable feedstocks such as lignocellulosic biomass. In this study, we cultivated yeast Trichosporon oleaginosus on hydrolysate of alkaline pretreated corn cobs. Different process configurations were evaluated and compared, including separate hydrolysis and fermentation (SHF) with cellulase recycle and simultaneous saccharification and fermentation (SSF) in batch and fed-batch mode. At low enzyme loading, the highest lipid concentration of 26.74 g L−1 was reached in fed-batch SSF fed with 2.5% (g g−1) substrate. Batch SHF was conducted for four rounds with recycling the cellulase adsorbed on unhydrolyzed lignocellulosic biomass. Thirty percent of cellulase saving was achieved for rounds 2–4 without compromising productivity and lipid yield. The addition of Tween 80 to lignocellulosic slurry improved the hydrolysis rate of structural carbohydrates in pretreated lignocellulosic biomass. Furthermore, supplementing the growth medium with Tween 80 improved lipid yield and productivity without affecting yeast growth. Oleaginous yeast T. oleaginosus is a promising strain for the sustainable and efficient production of lipids from renewable lignocellulosic feedstock.

The Effect of Mixed Culture of Zymomonas mobilis and Pichia stipitis in Ethanol Production of Sugar Palm (Arenga pinnata)

2019 ◽  
Vol 964 ◽  
pp. 145-150
Author(s):  
Anastasia Sandra Dewi ◽  
Richie Andyllo Stevanus ◽  
Maria Amelia Sandra ◽  
Dennis Farina Nury ◽  
Lily Pudjiastuti ◽  
...  
Keyword(s):  
Enzymatic Hydrolysis ◽  
Mixed Culture ◽  
Fermentation Process ◽  
Ethanol Concentration ◽  
Ethanol Yield ◽  
Tween 80 ◽  
Reducing Sugar ◽  
Organosolv Pretreatment ◽  
Mixed Culture Fermentation ◽  
Single Culture

In this study the effect of mixed culture of Zymomonasmobilis and Pichia stipitis to produce bioethanol from Solid Waste Arenga pinnata (SWAP) was investigated. The fermentation liquid substrate was resulted from an integrated process of pretreatment and enzymatic hydrolysis. Combination of diluted acid and ethanol organosolv pretreatment was used to increase the SWAP lignin removal. Raw pretreatment was used to decrease the SWAP particle size to 200 mesh. Acid pretreatment was done using 5% (v/v) diluted sulfate acid. Acid pretreated SWAP was treated for 65 min with organosolv pretreatment. Enzymatic hydrolysis by a combination of cellulase and xylanase was done for 48 h to convert cellulose into reducing sugar. The surfactants (Tween 80) addition was done to increase the sugar yield of the hydrolysis process. Fermentation variable consist of single culture of Z. mobilis as the control and mixed culture of Z. mobilis and P. stipitis, the microorganisms used to convert glucose and xylose into ethanol. The number of inoculum used in this experiment was more than 1.4 billion cells and the duration of fermentation process was 72 h. The delignification process decreased 95.43% lignin in SWAP. X-ray Diffraction (XRD) analysis assay showed an increase of crystallinity index of SWAP with pretreatment combination to 37.87%. Enzymatic hydrolysis by a combination of cellulase and xylanase with the addition of Tween 80 produced 9.16 gr glucose/L reducing sugar concentration. The highest ethanol resulted by fermentation process using mixed culture of Z. mobilis and P. stipitis with 0.33% (v/v) ethanol concentration and 0.57 (g ethanol/g reducing sugar) ethanol yield. Fermentation process using single culture Z. mobilis resulted 0.28% (v/v) ethanol concentration, and 0.48 (g ethanol/g reducing sugar) ethanol yield. The mixed culture fermentation with Z. mobilis and P. stipitis resulted ethanol yield 19 % higher than the single culture fermentation using Z. mobilis.

scholarly journals Batch and Fed-Batch Ethanol Fermentation of Cheese-Whey Powder with Mixed Cultures of Different Yeasts

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4495 ◽  
Author(s):  
Csilla Farkas ◽  
Judit M. Rezessy-Szabó ◽  
Vijai Kumar Gupta ◽  
Erika Bujna ◽  
Tuan M. Pham ◽  
...  
Keyword(s):  
Ethanol Production ◽  
Mixed Culture ◽  
Cheese Whey ◽  
Ethanol Concentration ◽  
Fed Batch ◽  
Batch Mode ◽  
Whey Powder ◽  
Cell Counts ◽  
Yeast Strains ◽  
Lactose Conversion

Eight yeast strains of Lachancea thermotolerans, Kluyveromyces marxianus, and Kluyveromyces waltii have been tested for their ability to ferment lactose into ethanol in mashes containing 10% (w/v) cheese whey powder (CWP). The K. marxianus NCAIM Y00963 achieved 3.5% (v/v) ethanol concentration at 96–120 h of fermentation. The ethanol production by the selected lactose-positive strains and the well-known ethanologenic Saccharomyces cerevisiae (Levuline Fb) in mixed culture was also investigated at different CWP concentrations and inoculation techniques in batch mode. The mixed culture in an equal ratio (1:1) of cell counts of K. marxianus and S. serevisiae showed an increase in lactose conversion rate. The two yeast strains in a ratio of 3:1 (three-quarters of K. marxianus and a quarter of S. cerevisiae in a total of 4.5 × 1010 cells) resulted in 72.33% efficiency of lactose bioconversion and 7.6% (v/v) ethanol production at 17.5% (w/v) of CWP concentration. In the repeated inoculation process, with the addition of three-quarter part of 3:1 ratio of mixed culture (3.3 × 1010 cells of K. marxianus) into 150 mL CWP mash at initiation and the rest quarter part (1.2 × 1010 cells of S. cerevisiae) at 24 h, 8.86% (v/v) ethanol content with 87.5% efficiency of lactose conversion was reached. Both the ethanol concentration and efficiency of bioconversion were increased to 10.34% (v/v) and 92%, respectively, by combination with fed-batch fermentation technology. Our results can serve a very good basis for the development of industrial technology for the utilization of cheese whey.

scholarly journals Hemicellulosic Bioethanol Production from Fast-Growing Paulownia Biomass

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 173
Author(s):  
Elena Domínguez ◽  
Pablo G. del Río ◽  
Aloia Romaní ◽  
Gil Garrote ◽  
Lucília Domingues
Keyword(s):  
Ethanol Production ◽  
Ethanol Concentration ◽  
Ethanol Yield ◽  
Xylose Reductase ◽  
Energy Crop ◽  
Scheffersomyces Stipitis ◽  
Fractionation Process ◽  
Renewable Source ◽  
Fast Growing ◽  
Engineered Strain

In order to exploit a fast-growing Paulownia hardwood as an energy crop, a xylose-enriched hydrolysate was obtained in this work to increase the ethanol concentration using the hemicellulosic fraction, besides the already widely studied cellulosic fraction. For that, Paulownia elongata x fortunei was submitted to autohydrolysis treatment (210 °C or S0 of 4.08) for the xylan solubilization, mainly as xylooligosaccharides. Afterwards, sequential stages of acid hydrolysis, concentration, and detoxification were evaluated to obtain fermentable sugars. Thus, detoxified and non-detoxified hydrolysates (diluted or not) were fermented for ethanol production using a natural xylose-consuming yeast, Scheffersomyces stipitis CECT 1922, and an industrial Saccharomyces cerevisiae MEC1133 strain, metabolic engineered strain with the xylose reductase/xylitol dehydrogenase pathway. Results from fermentation assays showed that the engineered S. cerevisiae strain produced up to 14.2 g/L of ethanol (corresponding to 0.33 g/g of ethanol yield) using the non-detoxified hydrolysate. Nevertheless, the yeast S. stipitis reached similar values of ethanol, but only in the detoxified hydrolysate. Hence, the fermentation data prove the suitability and robustness of the engineered strain to ferment non-detoxified liquor, and the appropriateness of detoxification of liquor for the use of less robust yeast. In addition, the success of hemicellulose-to-ethanol production obtained in this work shows the Paulownia biomass as a suitable renewable source for ethanol production following a suitable fractionation process within a biorefinery approach.

scholarly journals Screening for optimal protease producing Bacillus licheniformis strains with polymer-based controlled-release fed-batch microtiter plates

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Tobias Habicher ◽  
Tobias Klein ◽  
Jacqueline Becker ◽  
Andreas Daub ◽  
Jochen Büchs
Keyword(s):  
Controlled Release ◽  
Bacillus Licheniformis ◽  
Protease Activity ◽  
Microtiter Plate ◽  
Fed Batch ◽  
Batch Mode ◽  
Screening Process ◽  
Microtiter Plates ◽  
Batch Fermenter ◽  
Production Conditions

Abstract Background Substrate-limited fed-batch conditions have the favorable effect of preventing overflow metabolism, catabolite repression, oxygen limitation or inhibition caused by elevated substrate or osmotic concentrations. Due to these favorable effects, fed-batch mode is predominantly used in industrial production processes. In contrast, screening processes are usually performed in microtiter plates operated in batch mode. This leads to a different physiological state of the production organism in early screening and can misguide the selection of potential production strains. To close the gap between screening and production conditions, new techniques to enable fed-batch mode in microtiter plates have been described. One of these systems is the ready-to-use and disposable polymer-based controlled-release fed-batch microtiter plate (fed-batch MTP). In this work, the fed-batch MTP was applied to establish a glucose-limited fed-batch screening procedure for industrially relevant protease producing Bacillus licheniformis strains. Results To achieve equal initial growth conditions for different clones with the fed-batch MTP, a two-step batch preculture procedure was developed. Based on this preculture procedure, the standard deviation of the protease activity of glucose-limited fed-batch main culture cultivations in the fed-batch MTP was ± 10%. The determination of the number of replicates revealed that a minimum of 6 parallel cultivations were necessary to identify clones with a statistically significant increased or decreased protease activity. The developed glucose-limited fed-batch screening procedure was applied to 13 industrially-relevant clones from two B. licheniformis strain lineages. It was found that 12 out of 13 clones (92%) were classified similarly as in a lab-scale fed-batch fermenter process operated under glucose-limited conditions. When the microtiter plate screening process was performed in batch mode, only 5 out of 13 clones (38%) were classified similarly as in the lab-scale fed-batch fermenter process. Conclusion The glucose-limited fed-batch screening process outperformed the usual batch screening process in terms of the predictability of the clone performance under glucose-limited fed-batch fermenter conditions. These results highlight that the implementation of glucose-limited fed-batch conditions already in microtiter plate scale is crucial to increase the precision of identifying improved protease producing B. licheniformis strains. Hence, the fed-batch MTP represents an efficient high-throughput screening tool that aims at closing the gap between screening and production conditions.

Sign in / Sign up

Export Citation Format

Share Document