scholarly journals Enhancing Bioethanol Productivity Using Alkali-Pretreated Empty Palm Fruit Bunch Fiber Hydrolysate

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Seonghun Kim
Keyword(s):  
Sodium Hydroxide ◽  
Batch Fermentation ◽  
Ethanol Yield ◽  
Lignin Content ◽  
Enzymatic Saccharification ◽  
Renewable Resource ◽  
Palm Fruit ◽  
Fed Batch Fermentation ◽  
High Lignin Content ◽  
Simultaneous Saccharification

Empty palm fruit bunch fiber (EPFBF) is a renewable resource in oil palm plantations that can be used for lignocellulosic bioethanol production. To enhance ethanol productivity with high-lignin-content EPFBF, the biomass was prepared with an alkali-thermal pretreatment (sodium hydroxide, 121°C, 60 min). The delignification yield was 55.4–56.9%, in proportion to the amount of sodium hydroxide, from 0.5 to 2.0 M. The lignin and hemicellulose contents of EPFBF were reduced by the pretreatment process, whereas the proportion of cellulose was increased. During enzymatic saccharification using Celluclast 1.5L and Novozyme 188 enzyme cocktails, about 62% of glucan was converted to a fermentable sugar. In simultaneous saccharification and fermentation, comparison among three ethanologenic yeast strains showed Saccharomyces cerevisiae W303-1A to be a candidate for maximum ethanol yield. In a batch fermentation with alkali-pretreated EPFBF hydrolysate, 21 g/L ethanol was obtained within 28 h, for a production yield of 0.102 g ethanol/g dry EPFBF or 0.458 g ethanol/g glucose. Moreover, a fed-batch fermentation produced 33.8±0.5 g/L ethanol with 1.57 g/L/h productivity in 20 h. These results show that the combination of alkaline pretreatment and biomass hydrolysate is useful for enhancing bioethanol productivity using delignified EPFBF.

scholarly journals Evaluation of Alkali-Pretreated Soybean Straw for Lignocellulosic Bioethanol Production

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Seonghun Kim
Keyword(s):  
Sodium Hydroxide ◽  
Enzymatic Saccharification ◽  
Renewable Resource ◽  
Bioethanol Production ◽  
Yield Efficiency ◽  
Lignocellulosic Bioethanol ◽  
Acid Metabolites ◽  
Soybean Straw ◽  
Pretreated Biomass ◽  
Simultaneous Saccharification

Soybean straw is a renewable resource in agricultural residues that can be used for lignocellulosic bioethanol production. To enhance enzymatic digestibility and fermentability, the biomass was prepared with an alkali-thermal pretreatment (sodium hydroxide, 121°C, 60 min). The delignification yield was 34.1~53%, in proportion to the amount of sodium hydroxide, from 0.5 to 3.0 M. The lignin and hemicellulose contents of the pretreated biomass were reduced by the pretreatment process, whereas the proportion of cellulose was increased. Under optimal condition, the pretreated biomass consisted of 74.0±0.1% cellulose, 10.3±0.1% hemicellulose, and 10.1±0.6% lignin. During enzymatic saccharification using Cellic® CTec2 cellulase, 10% (w/v) of pretreated soybean straw was hydrolyzed completely and converted to 67.3±2.1 g/L glucose and 9.4±0.5 g/L xylose with a 90.9% yield efficiency. Simultaneous saccharification and fermentation of the pretreated biomass by Saccharomyces cerevisiae W303-1A produced 30.5±1.2 g/L ethanol in 0.5 L fermented medium containing 10% (w/v) pretreated biomass after 72 h. The ethanol productivity was 0.305 g ethanol/g dry biomass and 0.45 g ethanol/g glucose after fermentation, with a low concentration of organic acid metabolites. Also, 82% of fermentable sugar was used by the yeast for ethanol fermentation. These results show that the combination of alkaline pretreatment and biomass hydrolysate is useful for enhancing bioethanol productivity using delignified soybean straw.

scholarly journals Batch and Fed-Batch Fermentation System on Ethanol Production from Whey using Kluyveromyces marxianus

2013 ◽  
Vol 2 (3) ◽  
pp. 127-131 ◽  
Author(s):  
H Hadiyanto ◽  
D. Ariyanti ◽  
A.P. Aini ◽  
D.S. Pinundi
Keyword(s):  
Growth Rate ◽  
Ethanol Production ◽  
Kluyveromyces Marxianus ◽  
Batch Fermentation ◽  
Fermentation Process ◽  
Ethanol Yield ◽  
Fed Batch ◽  
Fermentation System ◽  
Batch System ◽  
Fed Batch Fermentation

Nowadays reserve of fossil fuel has gradually depleted. This condition forces many researchers to  find energy alternatives which is renewable and sustainable in the future. Ethanol derived from cheese industrial waste (whey) using fermentation process can be a new perspective in order to secure both energy and environment. The aim of this study was  to compare the operation modes (batch and fed-batch) of fermentation system on ethanol production from whey using Kluyveromyces marxianus. The result showed that the fermentation process for ethanol production by fed-batch system was higher at some point of parameters compared with batch system. Growth rate and ethanol yield (YP/S) of fed-batch fermentation were 0.122/h and 0.21 gP/gS respectively; growth rate and ethanol yield (YP/S) of batch fermentation were 0.107/h, and 0.12 g ethanol/g substrate, respectively. Based on the data of biomass and ethanol concentrations, the fermentation process for ethanol production by fed-batch system were higher at some point of parameters compared to batch system. Periodic substrate addition performed on fed-batch system leads the yeast growth in low substrate concentrations and consequently  increasing their activity and ethanol productivity. Keywords: batch; ethanol; fed-batch; fermentation;Kluyveromyces marxianus, whey

EVALUATION OF WASTE MUSHROOM MEDIUM AS A FERMENTABLE SUBSTRATE AND BIOETHANOL PRODUCTION

2012 ◽  
Vol 06 ◽  
pp. 745-750
Author(s):  
AI ASAKAWA ◽  
CHIZURU SASAKI ◽  
CHIKAKO ASADA ◽  
YOSHITOSHI NAKAMURA
Keyword(s):  
Steam Explosion ◽  
Lentinula Edodes ◽  
Simultaneous Saccharification And Fermentation ◽  
Ethanol Yield ◽  
Enzymatic Saccharification ◽  
Steam Pressure ◽  
Insoluble Residue ◽  
Steam Explosion Pretreatment ◽  
Simultaneous Saccharification ◽  
Waste Mushroom Medium

Waste Shiitake (Lentinula edodes) mushroom medium, a lignocellulosic aglicultural residue, was evaluated as a fermentable substrate. 87% of the fermentable sugars remained in the waste mushroom medium. The sugar yield of the waste mushroom medium (46.3%) was higher than that of raw mushroom medium (20.3%) after 48 h of enzymatic saccharification by Meicelase because L. edodes changed wood structure. These results indicated that the waste mushroom medium is a suitable substrate for fermentation. Next, the efficient ethanol production using steam explosion pretreatment was studied. After 30 h of simultaneous saccharification and fermentation (SSF) using Meicelase and Saccharomyces cerevisiae AM12, 20.0 g/L ethanol was produced from 100 g/L water-insoluble residue of the waste mushroom medium treated at a steam pressure of 20 atm and a steaming time of 5 min. This corresponded to an ethanol yield of 77.0% of the theoretical, i.e. 14.7 g of ethanol obtained from 100 g of waste mushroom medium.

scholarly journals Pretreatment of Corn Stover Using an Extremely Low-Liquid Ammonia (ELLA) Method for the Effective Utilization of Sugars in Simultaneous Saccharification and Fermentation (SSF) of Ethanol

Fermentation ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 191
Author(s):  
Tin Diep Trung Le ◽  
Vi Phuong Nguyen Truong ◽  
My Thi Tra Ngo ◽  
Tae Hyun Kim ◽  
Kyeong Keun Oh
Keyword(s):  
Corn Stover ◽  
Liquid Ammonia ◽  
Elevated Temperatures ◽  
Simultaneous Saccharification And Fermentation ◽  
Aqueous Ammonia ◽  
Ethanol Yield ◽  
Enzymatic Saccharification ◽  
Extended Period ◽  
Pretreatment Conditions ◽  
Simultaneous Saccharification

Extremely low-liquid ammonia (ELLA) pretreatment using aqueous ammonia was investigated in order to enhance the enzymatic saccharification of corn stover and subsequent ethanol production. In this study, corn stover was treated with an aqueous ammonia solution at different ammonia loading rates (0.1, 0.2, and 0.3 g NH3/g biomass) and various liquid-to-solid (L/S) ratios (0.55, 1.12, and 2.5). The ELLA pretreatment was conducted at elevated temperatures (90–150 °C) for an extended period (24–120 h). Thereafter, the pretreated material was saccharified by enzyme digestion and subjected to simultaneous saccharification and fermentation (SSF) tests. The effects of key parameters on both glucan digestibility and xylan digestibility were analyzed using analysis of variance (ANOVA). Under optimal pretreatment conditions (L/S = 2.5, 0.1 g-NH3/g-biomass, 150 °C), 81.2% glucan digestibility and 61.1% xylan digestibility were achieved. The highest ethanol yield achieved on the SSF tests was 85.4%. The ethanol concentration was 14.5 g/L at 96 h (pretreatment conditions: liquid-to-solid ratio (L/S) = 2.5, 0.1 g-NH3/g-biomass, 150 °C, 24 h. SSF conditions: microorganism Saccharomyces cerevisiae (D5A), 15 FPU/g-glucan, CTech2, 3% w/v glucan, 37 °C, 150 rpm).

scholarly journals Improving xylitol yield by deletion of endogenous xylitol-assimilating genes: a study of industrial Saccharomyces cerevisiae in fermentation of glucose and xylose

2020 ◽  
Vol 20 (8) ◽  
Author(s):  
Bai-Xue Yang ◽  
Cai-Yun Xie ◽  
Zi-Yuan Xia ◽  
Ya-Jing Wu ◽  
Min Gou ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Batch Fermentation ◽  
Xylose Reductase ◽  
Fed Batch ◽  
Fed Batch Fermentation ◽  
Engineered Saccharomyces Cerevisiae ◽  
Sorbitol Dehydrogenases ◽  
Simultaneous Saccharification ◽  
Xylitol Yield ◽  
Endogenous Enzymes

ABSTRACT Engineered Saccharomyces cerevisiae can reduce xylose to xylitol. However, in S.cerevisiae, there are several endogenous enzymes including xylitol dehydrogenase encoded by XYL2, sorbitol dehydrogenases encoded by SOR1/SOR2 and xylulokinase encoded by XKS1 may lead to the assimilation of xylitol. In this study, to increase xylitol accumulation, these genes were separately deleted through CRISPR/Cas9 system. Their effects on xylitol yield of an industrial S. cerevisiae CK17 overexpressing Candida tropicalis XYL1 (encoding xylose reductase) were investigated. Deletion of SOR1/SOR2 or XKS1 increased the xylitol yield in both batch and fed-batch fermentation with different concentrations of glucose and xylose. The analysis of the transcription level of key genes in the mutants during fed-batch fermentation suggests that SOR1/SOR2 are more crucially responsible for xylitol oxidation than XYL2 under the genetic background of S.cerevisiae CK17. The deletion of XKS1 gene could also weaken SOR1/SOR2 expression, thereby increasing the xylitol accumulation. The XKS1-deleted strain CK17ΔXKS1 produced 46.17 g/L of xylitol and reached a xylitol yield of 0.92 g/g during simultaneous saccharification and fermentation (SSF) of pretreated corn stover slurry. Therefore, the deletion of XKS1 gene provides a promising strategy to meet the industrial demands for xylitol production from lignocellulosic biomass.

scholarly journals Bioethanol Production From Pennisetum sp. Using Fed-Batch Simultaneous Saccharification and Co-Fermentation at High Solid Loadings and Its Life Cycle Analysis

2020 ◽  
Author(s):  
Sonai Mohapatra ◽  
Bikash Chandra Behera ◽  
Achuyta Nanda Acharya ◽  
Hrudayanath thatoi
Keyword(s):  
Life Cycle ◽  
Ethanol Production ◽  
Life Cycle Analysis ◽  
Batch Fermentation ◽  
Shake Flask ◽  
Feeding Strategy ◽  
Bioethanol Production ◽  
Fed Batch ◽  
Fed Batch Fermentation ◽  
Simultaneous Saccharification

Abstract Considerable progress has been achieved for production of bioethanol from lignocellulosic biomass. However, increasing the substrate concentration has shown to decrease the ethanol productivity. In the present study, Saccharomyces cerevisiae and Pichia membreneferans were used for ethanol production from glucose and xylose sugars respectively in optimized conditions. Further, co-culture fermentations were conducted in three different strategies for 13 g of sugar (10 g of glucose and 3 g of xylose) and the best strategy was further used for ethanol production from ultrasonication assisted NaOH (UA-NaOH) pretreated and enzymatically saccharified in batch and fed-batch fermentation conditions. Further, fed-batch fermentation was used for separate hydrolysis and co-fermentation (SHCF) and simultaneous saccharification and co-fermentation (SSCF) in shake flask conditions. The highest ethanol production of 12.2 and 7.9 (g/L) was observed for fed-batch SSCF denannath grass (DG) and Hybrid napier grass (HNG) (Palkonal MBW as the enzyme) biomass (80 g) respectively in shake flask conditions. However, increasing the biomass concentration to 270 g produced an ethanol concentration of 77.6 and 51.3 (g/L) for DG and HNG respectively in fed-batch SSCF conditions in bioreactor. Nuclear magnetic resonance studies of the residual biomass of both DG and HNG revealed presence of lower carbohydrate content, demonstrating the efficiency of the fermentation strategy. Further Life cycle Analysis (LCA) was also conducted to analyzed the effect of the ethanol on different environmental conditionsThe substrate feeding strategy and the saccharifying enzymes play a major role for efficient bioethanol production with higher substrate loadings. Presence of lower carbohydrates and some lignin moieties demonstrating the efficiency of the SSCF strategy for maximum conversion of carbohydrates. Thus fed batch SSCF process can be considered as a promising technique for biorefinery based bioethanol production from Pennisetum sp. in the future.

scholarly journals Batch Fermentation Options for High Titer Bioethanol Production from a SPORL Pretreated Douglas-fir Forest Residue without Detoxification

2016 ◽  
Author(s):  
Mingyan Yang ◽  
Hairui Ji ◽  
J.Y. ZHU
Keyword(s):  
Batch Fermentation ◽  
Simultaneous Saccharification And Fermentation ◽  
Ethanol Yield ◽  
High Titer ◽  
Douglas Fir ◽  
Bioethanol Production ◽  
Enzyme Loading ◽  
Nutrient Supplementation ◽  
Forest Residue ◽  
Simultaneous Saccharification

This study evaluated batch fermentation modes, namely, separate hydrolysis and fermentation (SHF), Quasi-simultaneous saccharification and fermentation (Q-SSF), and simultaneous saccharification and fermentation (SSF), and fermentation conditions, i.e., enzyme and yeast loadings, nutrient supplementation and sterilization, on high titer bioethanol production from SPORL-pretreated Douglas-fir forest residue without detoxification. The result indicated Q-SSF and SSF were obviously superior to SHF operation in terms of ethanol yield. The enzyme loading showed a strong positive correlation between enzyme loading and the ethanol yield. The nutrient supplementation and sterility was not necessary for ethanol production from SPORL-pretreated Douglas-fir. The yeast loading showed no significant influence on the ethanol yield for typical SSF conditions. The terminal ethanol titer of 43.2 g/L, or 75.1% theoretical based on glucose, mannose, and xylose theoretical was achieved when SSF was conducted at the condition of following: whole slurry solids loading of 15%, enzyme loading of 20 FPU/g glucan, 1.8 g/kg (wet) yeast loading, without nutrition supplementation and sterilization, at 38°C, on shake flask at 150 rpm for 96h. It is believed that with mechanical mixing, enzyme loading can be substantially reduced with affect ethanol yield by using a long fermentation time.

scholarly journals Bioethanol Production From Pineapple Wastes

2014 ◽  
Vol 3 (4) ◽  
pp. 60 ◽  
Author(s):  
Alessia Tropea ◽  
David Wilson ◽  
Loredana G. La Torre ◽  
Rosario B. Lo Curto ◽  
Peter Saugman ◽  
...  
Keyword(s):  
Plant Cell ◽  
Cell Walls ◽  
Simultaneous Saccharification And Fermentation ◽  
Ethanol Yield ◽  
Enzymatic Saccharification ◽  
Plant Cell Walls ◽  
Theoretical Yield ◽  
Cellulosic Sugars ◽  
Separate Hydrolysis And Fermentation ◽  
Simultaneous Saccharification

<p>There is great interest in producing bioethanol from biomass and there is much emphasis on exploiting lignocellulose sources, from crop wastes through to energy-rich crops. Some waste streams, however, contain both cellulosic and non-cellulosic sugars. These include wastes from pineapple processing.</p> <p>Pineapple wastes are produced in large amounts throughout the world by canning industries. These wastes are rich in intracellular sugars and plant cell walls which are composed mainly of cellulose, pectic substances and hemicelluloses. The purpose of this study was to investigate the potential to transform such residues into ethanol after enzymatic saccharification of plant cell walls, and fermentation of the resulting simple sugars using the <em>Saccharomyces cerevisiae</em> NCYC 2826 strain. Three different fermentation modes, direct fermentation, separate hydrolysis and fermentation, and simultaneous saccharification and fermentation of the biomass were tested and compared. The results show that the main sugars obtained from pineapple waste were: glucose, uronic acid, xylose, galactose, arabinose and mannose. The highest ethanol yield was achieved after 30 hours of simultaneous saccharification and fermentation, and reached up to 3.9% (v/v), corresponding to the 96% of the theoretical yield.</p>

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