scholarly journals Impacts of lignin contents and yeast extract addition on the interaction between spruce pulps and crude recombinant Paenibacillus endoglucanase

BioResources ◽  
2011 ◽  
Vol 6 (1) ◽  
pp. 853-866
Author(s):  
Chun-Han Ko ◽  
Fang-Jing Chen ◽  
Wan-Jyung Liao ◽  
Tzenge-Lien Shih
Keyword(s):  
Nitrogen Source ◽  
Yeast Extract ◽  
Rate Constants ◽  
Degradation Rate ◽  
Reducing Sugars ◽  
Simultaneous Saccharification And Fermentation ◽  
Degree Of Polymerization ◽  
Fermentation Processes ◽  
Gain Access ◽  
Simultaneous Saccharification

Crude recombinant Paenibacillus endoglucanase was employed to investigate its ability to gain access into and to degrade spruce pulps having different lignin and pentosan contents. Since yeast extract is commonly present in the simultaneous saccharification and fermentation processes as a nitrogen source, its effect on the accessibility and degradability of crude endoglucanase was examined. Pulps with more lignin contents adsorbed more overall proteins. More protein impurities other than the recombinant Paenibacillus endoglucanase were found to be preferentially adsorbed on the surfaces of pulp with higher lignin contents. The addition of yeast extracts further enhanced the above trends, which might reduce the non-productive binding by pulp lignin. Pulps with more lignin contents were more difficult to be degraded by the crude endoglucanase; the reductions of degree of polymerization (DP) for pulps were more sensitive to the dosage of endoglucanase applied. The presence of yeast extracts increased the DP degradation rate constants, but decreased the release of reducing sugars during hydrolysis for pulp with higher lignin contents.

scholarly journals Enhancing Hydrogen Production from Chlorella sp. Biomass by Pre-Hydrolysis with Simultaneous Saccharification and Fermentation (PSSF)

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 908 ◽  
Author(s):  
Tran Giang ◽  
Siriporn Lunprom ◽  
Qiang Liao ◽  
Alissara Reungsang ◽  
Apilak Salakkam
Keyword(s):  
Hydrogen Production ◽  
Reducing Sugars ◽  
Simultaneous Saccharification And Fermentation ◽  
Hydrogen Yield ◽  
Microalgal Biomass ◽  
Fermentation Time ◽  
Chlorella Sp ◽  
Volatile Solids ◽  
Filter Paper Unit ◽  
Simultaneous Saccharification

Simultaneous saccharification and fermentation (SSF) and pre-hydrolysis with SSF (PSSF) were used to produce hydrogen from the biomass of Chlorella sp. SSF was conducted using an enzyme mixture consisting of 80 filter paper unit (FPU) g-biomass−1 of cellulase, 92 U g-biomass−1 of amylase, and 120 U g-biomass−1 of glucoamylase at 35 °C for 108 h. This yielded 170 mL-H2 g-volatile-solids−1 (VS), with a productivity of 1.6 mL-H2 g-VS−1 h−1. Pre-hydrolyzing the biomass at 50 °C for 12 h resulted in the production of 1.8 g/L of reducing sugars, leading to a hydrogen yield (HY) of 172 mL-H2 g-VS−1. Using PSSF, the fermentation time was shortened by 36 h in which a productivity of 2.4 mL-H2 g-VS−1 h−1 was attained. To the best of our knowledge, the present study is the first report on the use of SSF and PSSF for hydrogen production from microalgal biomass, and the HY obtained in the study is by far the highest yield reported. Our results indicate that PSSF is a promising process for hydrogen production from microalgal biomass.

scholarly journals Evolutionary engineering of Lactobacillus bulgaricus reduces enzyme usage and enhances conversion of lignocellulosics to D-lactic acid by simultaneous saccharification and fermentation

2020 ◽  
Author(s):  
Vishnu Prasad J. ◽  
Tridweep K. Sahoo ◽  
Naveen S. ◽  
Guhan Jayaraman
Keyword(s):  
Lactic Acid ◽  
Simultaneous Saccharification And Fermentation ◽  
Enzyme Hydrolysis ◽  
Lactobacillus Bulgaricus ◽  
Evolutionary Engineering ◽  
Enzyme Loading ◽  
Promising Alternative ◽  
Fermentation Processes ◽  
Platform Chemicals ◽  
Simultaneous Saccharification

Abstract BackgroundSimultaneous saccharification and fermentation (SSF) of pre-treated lignocellulosics to biofuels and other platform chemicals has long been a promising alternative to separate hydrolysis and fermentation processes. However, the disparity between the optimum conditions (temperature, pH) for fermentation and enzyme hydrolysis leads to execution of the SSF process at sub-optimal conditions, which can affect the rate of hydrolysis and cellulose conversion. The fermentation conditions could be synchronized with hydrolysis optima by carrying out the SSF at a higher temperature, but this would require a thermo-tolerant organism. Economically viable production of platform chemicals from lignocellulosic biomass (LCB) has long been stymied because of the significantly higher cost of hydrolytic enzymes. The major objective of this work is to develop an SSF strategy for D- lactic acid production by a thermo-tolerant organism, in which the enzyme loading could significantly be reduced without compromising on the overall conversion.ResultsA thermo-tolerant strain of Lactobacillus bulgaricus was developed by adaptive laboratory evolution (ALE) which enabled the SSF to be performed at 45 °C with reduced enzyme usage. Despite the reduction of enzyme loading from 15 Filter Paper Unit/ gLCB (FPU/gLCB) to 5 FPU/gLCB, we could still achieve ~8% higher cellulose to D-Lactic acid (D-LA) conversion in batch SSF, in comparison to the conversion by separate enzymatic hydrolysis and fermentation processes at 45 °C and pH 5.5. Extending the batch SSF to SSF with pulse-feeding of 5% pre-treated biomass and 5 FPU/gLCB, at 12-hour intervals (36th h – 96th h), resulted in a titer of 108 g/L D-LA and 60% conversion of cellulose to D-LA. This is one among the highest reported D-LA titers achieved from LCB.ConclusionsWe have demonstrated that the SSF strategy, in conjunction with evolutionary engineering, could drastically reduce enzyme requirement and be the way forward for economical production of platform chemicals from lignocellulosics. We have shown that fed-batch SSF processes, designed with multiple pulse-feedings of the pre-treated biomass and enzyme, can be an effective way of enhancing the product concentrations.

scholarly journals Evolutionary Engineering of Lactobacillus Bulgaricus Reduces Enzyme Usage and Enhances Conversion of Lignocellulosics to D-lactic Acid by Simultaneous Saccharification and Fermentation

2020 ◽  
Author(s):  
Vishnu Prasad J. ◽  
Tridweep K. Sahoo ◽  
Naveen S. ◽  
Guhan Jayaraman
Keyword(s):  
Lactic Acid ◽  
Lignocellulosic Biomass ◽  
Simultaneous Saccharification And Fermentation ◽  
Enzyme Hydrolysis ◽  
Lactobacillus Bulgaricus ◽  
Evolutionary Engineering ◽  
Enzyme Loading ◽  
Fermentation Processes ◽  
Platform Chemicals ◽  
Simultaneous Saccharification

Abstract BackgroundSimultaneous saccharification and fermentation (SSF) of pre-treated lignocellulosics to biofuels and other platform chemicals has long been a promising alternative to separate hydrolysis and fermentation processes. However, the disparity between the optimum conditions (temperature, pH) for fermentation and enzyme hydrolysis leads to execution of the SSF process at sub-optimal conditions, which can affect the rate of hydrolysis and cellulose conversion. The fermentation conditions could be synchronized with hydrolysis optima by carrying out the SSF at a higher temperature, but this would require a thermo-tolerant organism. Economically viable production of platform chemicals from lignocellulosic biomass has long been stymied because of the significantly higher cost of hydrolytic enzymes. The major objective of this work is to develop an SSF strategy for D- lactic acid production by a thermo-tolerant organism, in which the enzyme loading could significantly be reduced without compromising on the overall conversion. ResultsA thermo-tolerant strain of Lactobacillus bulgaricuswas developed by adaptive laboratory evolution (ALE) which enabled the SSF to be performed at 45 °C with reduced enzyme usage.Despite the reduction of enzyme loading from 15 FPU/gbiomass to 5 FPU/gbiomass, we could still achieve ~8% higher cellulose to D-LA conversion in batch SSF, in comparison to the conversion by separate enzymatic hydrolysis and fermentation processes at 45 °C and pH 5.5. Extending the batch SSF to an SSF with pulse-feeding of 5% pre-treated biomass and 5 FPU/g-biomass, at12-hour intervals (36th h – 96th h), resulted in a titer of 108 g/L D-LA and 60% conversion of cellulose to D-LA.This is one among the highest reported D-LA titers achieved from lignocellulosic biomass.ConclusionsWe have demonstrated that the SSF strategy, in conjunction with evolutionary engineering, could drastically reduce enzyme requirement and be the way forward for economical production of platform chemicals from lignocellulosics. We have shown that fed-batch SSF processes, designed with multiple pulse-feedings of the pre-treated biomass and enzyme, can be an effective way of enhancing the product concentrations.

Proper ultrasound treatment increases ethanol production from simultaneous saccharification and fermentation of sugarcane bagasse

RSC Advances ◽  
2016 ◽  
Vol 6 (94) ◽  
pp. 91409-91419 ◽  
Author(s):  
Rajendran Velmurugan ◽  
Aran Incharoensakdi
Keyword(s):  
Ethanol Production ◽  
Sugarcane Bagasse ◽  
Simultaneous Saccharification And Fermentation ◽  
Ethanol Yield ◽  
Ultrasound Treatment ◽  
Fermentation Processes ◽  
Cellulase Complex ◽  
Simultaneous Saccharification

To improve the saccharification and fermentation processes, proper ultrasound was applied which resulted in the presence of cellulase complex with improved β-glucosidase ratio leading to enhanced overall ethanol yield.

scholarly journals Evolutionary engineering of Lactobacillus bulgaricus reduces enzyme usage and enhances conversion of lignocellulosics to D-lactic acid by simultaneous saccharification and fermentation

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
J. Vishnu Prasad ◽  
Tridweep K. Sahoo ◽  
S. Naveen ◽  
Guhan Jayaraman
Keyword(s):  
Lactic Acid ◽  
Simultaneous Saccharification And Fermentation ◽  
Enzyme Hydrolysis ◽  
Lactobacillus Bulgaricus ◽  
Evolutionary Engineering ◽  
Enzyme Loading ◽  
Promising Alternative ◽  
Fermentation Processes ◽  
Platform Chemicals ◽  
Simultaneous Saccharification

Abstract Background Simultaneous saccharification and fermentation (SSF) of pre-treated lignocellulosics to biofuels and other platform chemicals has long been a promising alternative to separate hydrolysis and fermentation processes. However, the disparity between the optimum conditions (temperature, pH) for fermentation and enzyme hydrolysis leads to execution of the SSF process at sub-optimal conditions, which can affect the rate of hydrolysis and cellulose conversion. The fermentation conditions could be synchronized with hydrolysis optima by carrying out the SSF at a higher temperature, but this would require a thermo-tolerant organism. Economically viable production of platform chemicals from lignocellulosic biomass (LCB) has long been stymied because of the significantly higher cost of hydrolytic enzymes. The major objective of this work is to develop an SSF strategy for D-lactic acid (D-LA) production by a thermo-tolerant organism, in which the enzyme loading could significantly be reduced without compromising on the overall conversion. Results A thermo-tolerant strain of Lactobacillus bulgaricus was developed by adaptive laboratory evolution (ALE) which enabled the SSF to be performed at 45 °C with reduced enzyme usage. Despite the reduction of enzyme loading from 15 Filter Paper Unit/gLCB (FPU/gLCB) to 5 FPU/gLCB, we could still achieve ~ 8% higher cellulose to D-LA conversion in batch SSF, in comparison to the conversion by separate enzymatic hydrolysis and fermentation processes at 45 °C and pH 5.5. Extending the batch SSF to SSF with pulse-feeding of 5% pre-treated biomass and 5 FPU/gLCB, at 12-h intervals (36th–96th h), resulted in a titer of 108 g/L D-LA and 60% conversion of cellulose to D-LA. This is one among the highest reported D-LA titers achieved from LCB. Conclusions We have demonstrated that the SSF strategy, in conjunction with evolutionary engineering, could drastically reduce enzyme requirement and be the way forward for economical production of platform chemicals from lignocellulosics. We have shown that fed-batch SSF processes, designed with multiple pulse-feedings of the pre-treated biomass and enzyme, can be an effective way of enhancing the product concentrations.

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