De-ashing treatment of corn stover improves the efficiencies of enzymatic hydrolysis and consequent ethanol fermentation

He, Yanqing; Fang, Zhenhong; Zhang, Jian; Li, Xinliang; Bao, Jie

doi:10.1016/j.biortech.2014.06.088

Cited by 49 publications

(43 citation statements)

References 17 publications

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“…No consumption of sugar was observed for the engineered E. coli strain without rpe and pgi when xylose or glucose was used as the sole carbon source (Gawand et al 2013). In cellulosic ethanol production processes, hydrolysates from the biomass pretreated with dilute acids or steam explosion or hot water have high concentrations of glucose and low concentrations of xylose (He et al 2014;Liu et al 2013). Therefore, although SyBE_Sc17004 cannot consume xylose as the sole carbon source, it exhibited the potential applications for such hydrolysates with high glucose and low xylose content as mentioned above due to the potential of the simultaneous utilization of xylose and glucose for shortening the whole fermentation process.…”

Section: Xylose-utilizing Yeast Constructionmentioning

confidence: 88%

Deletion of d-ribulose-5-phosphate 3-epimerase (RPE1) induces simultaneous utilization of xylose and glucose in xylose-utilizing Saccharomyces cerevisiae

Shen

Song

et al. 2014

Biotechnol Lett

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Simultaneous co-utilization of xylose and glucose is a key issue in engineering microbes for cellulosic ethanol production. We coupled xylose utilization with glucose metabolism by deletion of D-ribulose-5-phosphate 3-epimerase (RPE1) through pentose phosphate pathway flux. Simultaneous utilization of xylose and glucose then occurred in the engineered Saccharomyces cerevisiae strain with the xylose utilization pathway. Xylose consumption occurred at the beginning of glucose consumption by the engineered yeast without RPE1 in a mixed sugar fermentation. About 3.2 g xylose l(-1) was utilized simultaneously with consumption of 40.2 g glucose l(-1) under O2-limited conditions. In addition, an approximate ratio (~1:10) for xylose and glucose consumption was observed in the fermentation with different sugar concentration by the engineered strain without RPE1. Simultaneous utilization of xylose is realized by the coupling of glucose metabolism and xylose utilization through RPE1 deletion in xylose-utilizing S. cerevisiae.

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Section: Xylose-utilizing Yeast Constructionmentioning

confidence: 88%

Deletion of d-ribulose-5-phosphate 3-epimerase (RPE1) induces simultaneous utilization of xylose and glucose in xylose-utilizing Saccharomyces cerevisiae

Shen

Song

et al. 2014

Biotechnol Lett

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“…Single colonies were transferred from agar plates to a sterile medium containing 10 g/L 15 glucose, 20 g/L xylose, 3 g/L yeast extract, 5 g/L peptone, 2.3 g/L urea, and 1 g/L MgSO4·7H2O. The 16 inoculum was grown at 30ºC with constant orbital mixing (175 rpm) for 48h. Cells were harvested by 17 centrifugation at 3,000 rpm for 5 minutes at room temperature.…”

Section: Microorganism and Media 13mentioning

confidence: 99%

Novel ethanol production using biomass preprocessing to increase ethanol yield and reduce overall costs

Pascoli

Suko

Gustafson

et al. 2020

Preprint

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1 Background: Ethanol biorefineries need to lower their overall production costs to become economically 2 feasible. Two strategies to achieve this are to reduce costs by using cheaper feedstocks or to increase the 3 ethanol production yield. Low-cost feedstocks usually have high non-structural components (NSC) content, 4 therefore a new process is necessary to accommodate these feedstocks and overcome the negative effects 5 of NSC. This study developed a novel ethanol biorefinery process including a biomass preprocessing step 6 that enabled the use of lower-cost feedstocks while improving ethanol production without detoxification 7 (overliming). Two types of poplar feedstocks were used, low-quality whole-tree chips (WTC) and high-8quality clean pulp chips (CPC), to determine if the proposed process is effective while using feedstocks 9 with different NSC contents. 10Results: Technical assessment showed that acidic preprocessing increased the monomeric sugar recovery 11 of WTC from 73.2% (untreated) to 87.5% due to reduced buffering capacity of poplar, improved sugar 12 solubilization during pretreatment, and better enzymatic hydrolysis conversion. Preprocessing alone 13 significantly improved the fermentability of the liquid fraction from 1-2% to 49-56% for both feedstocks, 14 while overliming improved it to 45%. Consequently, it was proposed that preprocessing can substitute for 15 the detoxification step. The economic assessment revealed that using poplar WTC via the new process 16 increased annual ethanol production of 10.5 million liters when compared to using CPC via overliming 17 (base case scenario). Also, savings in total operating costs were about $10 million per year when using 18 cheaper poplar WTC instead of CPC, and by using recycled water for preprocessing lowered its total 19 operating costs by 45-fold. 20 Conclusions:The novel process developed in this study was successful in increasing ethanol production 21 while decreasing overall costs, thus facilitating the feasibility of lignocellulosic ethanol biorefineries. Key 22 factors to achieving this outcome included substituting overliming by preprocessing, enabling the use of 23 lower-quality feedstock, increasing monomeric sugar recovery and ethanol fermentation yield, and using 24 recycled water for preprocessing. In addition, preprocessing enabled the implementation of an evaporator-1 combustor downstream design, resulting in a low-loading waste stream that can be treated in a wastewater 2 treatment plant with a simple configuration. 3

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“…Residual xylan in pretreated residues has been described to exert a "blocking effect" upon the substrate's surface, which renders unsuccessful enzymatic digestion [39]. To negate or eliminate the unwanted buffering effects caused by ash during autohydrolysis, strategies of de-washing and adding of sulfuric acid and exchangeable metal salts have been successfully applied in previous work [21,40,41]. Previous studies have also observed that the removal of organic matter alone from the soluble mixtures of EA can lead to an increasing enzymatic digestibility of autohydrolyzed WS with EA components [28].…”

Section: Effects Of Loading Buffering Compounds On the Enzymatic Digementioning

confidence: 99%

“…Phosphate, as the main component of phosphate fertilizers, has also been shown to behave as a pH buffering compound when found in aqueous media [15]. This is particularly problematic for autohydrolysis, as He et al (2014) found that over 2.5 wt% phosphorus existed in ash derived from corn stover. The remaining phosphorus would be released in the form of phosphate which could further in uence lignocellulosic autohydrolysis.…”

Section: Introductionmentioning

confidence: 99%

Unrevealing model compounds of soil conditioners impacts on the wheat straw autohydrolysis efficiency and enzymatic hydrolysis

Tang

Huang

et al. 2020

Preprint

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Background: Soil-derived exogenous ash (EA) poses a challenge toward lignocellulosics autohydrolysis due to its buffering capacity. Previous works focusing on this phenomenon have failed to also investigate the role that soluble salts, and organic matter plays in this system. Herein, sodium phosphate and sodium humate were employed as model buffering compounds representing soluble salts and organic matter and dosed into a de-ashed wheat straw (DWS) autohydrolysis process to show the potential impacts of WS attached soil conditioners on the WS autohydrolysis efficiency which would further affect the enzymatic digestibility of autohydrolyzed WS.Results: Results showed that with the increasing loadings of sodium phosphate and sodium humate resulted in elevated pH values (from 4.0 to 5.1 and from 4.1 to 4.7, respectively). Meanwhile, the reductions of xylan removal yields from ~84.3-61.4% to 72.3-53.0% by loading (1~30 g/L) sodium phosphate and sodium humate during WS autohydrolysis lead to a significant decrease of cellulose accessibilities which finally lead to a reduction of the enzymatic digestibility of autohydrolyzed WS from ~75.4-77.2% to 47.3-57.7%.Conclusion: The existence of different types soil conditioner model compounds result in various component fractions from autohydrolyzed WS in the process of autohydrolysis. A lack of sufficient xylan removal was found to drive the significant decrease in enzymatic accessibility. The results demonstrated the various effects of two typical tested soil conditioners on WS autohydrolysis and enzymatic hydrolysis.

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De-ashing treatment of corn stover improves the efficiencies of enzymatic hydrolysis and consequent ethanol fermentation

Cited by 49 publications

References 17 publications

Deletion of d-ribulose-5-phosphate 3-epimerase (RPE1) induces simultaneous utilization of xylose and glucose in xylose-utilizing Saccharomyces cerevisiae

Deletion of d-ribulose-5-phosphate 3-epimerase (RPE1) induces simultaneous utilization of xylose and glucose in xylose-utilizing Saccharomyces cerevisiae

Novel ethanol production using biomass preprocessing to increase ethanol yield and reduce overall costs

Unrevealing model compounds of soil conditioners impacts on the wheat straw autohydrolysis efficiency and enzymatic hydrolysis

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