Performance of a newly developed integrant of Zymomonas mobilis for ethanol production on corn stover hydrolysate

Mohagheghi, Ali; Dowe, Nancy; Schell, Daniel J.; Chou, Yat‐Chen; Eddy, C K; Zhang, Min

doi:10.1023/b:bile.0000015451.96737.96

Cited by 77 publications

(62 citation statements)

References 11 publications

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“…Compared with the results with pure sugars, ethanol productions in hydrolysates were impeded significantly (Bothast et al 1999;Feng et al 2012;Jennings and Schell 2011;Jeon et al 2010;Joachimsthal et al 1999;Krishnan et al 2000;Mohagheghi et al 2002Mohagheghi et al , 2004Schell et al 2016;Serate et al 2015;Teixeira et al 2000;Yanase et al 2012;Zhao et al 2014). For example, the ethanol yield was much lower in the hydrolysate (15 g/L) than in pure glucose fermentation (44.9 g/L) (Dong et al 2013;Zhao et al 2014).…”

Section: Evaluation Of the Effect Of Hydrolysate Inhibitors On Z Mobmentioning

confidence: 90%

Progress and perspective on lignocellulosic hydrolysate inhibitor tolerance improvement in Zymomonas mobilis

Yang

Tang

et al. 2018

Bioresour. Bioprocess.

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Pretreatment is the key step to overcome the recalcitrance of lignocellulosic biomass making sugars available for subsequent enzymatic hydrolysis and microbial fermentation. During the process of pretreatment and enzymatic hydrolysis as well as fermentation, various toxic compounds may be generated with strong inhibition on cell growth and the metabolic capacity of fermenting strains. Zymomonas mobilis is a natural ethanologenic bacterium with many desirable industrial characteristics, but it can also be severely affected by lignocellulosic hydrolysate inhibitors. In this review, analytical methods to identify and quantify potential inhibitory compounds generated during lignocellulose pretreatment and enzymatic hydrolysis were discussed. The effect of hydrolysate inhibitors on Z. mobilis was also summarized as well as corresponding approaches especially the high-throughput ones for the evaluation. Then the strategies to enhance inhibitor tolerance of Z. mobilis were presented, which include both forward and reverse genetics approaches such as classical and novel mutagenesis approaches, adaptive laboratory evolution, as well as genetic and metabolic engineering. Moreover, this review provided perspectives and guidelines for future developments of robust strains for efficient bioethanol or biochemical production from lignocellulosic materials.

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Section: Evaluation Of the Effect Of Hydrolysate Inhibitors On Z Mobmentioning

confidence: 90%

Progress and perspective on lignocellulosic hydrolysate inhibitor tolerance improvement in Zymomonas mobilis

Yang

Tang

et al. 2018

Bioresour. Bioprocess.

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“…Ethanologenic Escherichia coli strains containing the pdc and adh genes from Zymomonas mobilis ferment both hexoses and pentoses to ethanol at a high rate and yield (11). Genetic engineering of S. cerevisiae and Z. mobilis by adding genes for pentose utilization has yet to produce a biocatalyst that matches the pentose fermentation characteristics of recombinant ethanologenic E. coli (14,22). However, the use of a recombinant organism for large-scale fuel production is perceived by some as a barrier to commercialization.…”

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confidence: 99%

Construction of an Escherichia coli K-12 Mutant for Homoethanologenic Fermentation of Glucose or Xylose without Foreign Genes

Kim

Ingram

Shanmugam

2007

Appl Environ Microbiol

128

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Conversion of lignocellulosic feedstocks to ethanol requires microorganisms that effectively ferment both hexose and pentose sugars. Towards this goal, recombinant organisms have been developed in which heterologous genes were added to platform organisms such as Saccharomyces cerevisiae, Zymomonas mobilis, and Escherichia coli. Using a novel approach that relies only on native enzymes, we have developed a homoethanologenic alternative, Escherichia coli strain SE2378. This mutant ferments glucose or xylose to ethanol with a yield of 82% under anaerobic conditions. An essential mutation in this mutant was mapped within the pdh operon (pdhR aceEF lpd), which encodes components of the pyruvate dehydrogenase complex. Anaerobic ethanol production by this mutant is apparently the result of a novel pathway that combines the activities of pyruvate dehydrogenase (typically active during aerobic, oxidative metabolism) with the fermentative alcohol dehydrogenase.

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“…Previous work with the microorganism used in this study showed high tolerance to acetic acid (Mohagheghi et al, 2004). Examination of the pure sugar control fermentation data along with the results presented in Figure 1 suggest that increasing acetic acid concentrations have a slight but increasingly negative impact on ethanol yield.…”

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confidence: 53%

Impact of recycling stillage on conversion of dilute sulfuric acid pretreated corn stover to ethanol

Mohagheghi

Schell

2010

Biotech & Bioengineering

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Both the current corn starch to ethanol industry and the emerging lignocellulosic biofuels industry view recycling of spent fermentation broth or stillage as a method to reduce fresh water use. The objective of this study was to understand the impact of recycling stillage on conversion of corn stover to ethanol. Sugars in a dilute-acid pretreated corn stover hydrolysate were fermented to ethanol by the glucose-xylose fermenting bacteria Zymomonas mobilis 8b. Three serial fermentations were performed at two different initial sugar concentrations using either 10% or 25% of the stillage as makeup water for the next fermentation in the series. Serial fermentations were performed to achieve near steady state concentration of inhibitors and other compounds in the corn stover hydrolysate. Little impact on ethanol yields was seen at sugar concentrations equivalent to pretreated corn stover slurry at 15% (w/w) with 10% recycle of the stillage. However, ethanol yields became progressively poorer as the sugar concentration increased and fraction of the stillage recycled increased. At an equivalent corn stover slurry concentration of 20% with 25% recycled stillage the ethanol yield was only 5%. For this microorganism with dilute-acid pretreated corn stover, recycling a large fraction of the stillage had a significant negative impact on fermentation performance. Although this finding is of concern for biochemical-based lignocellulose conversion processes, other microorganism/pretreatment technology combinations will likely perform differently.

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Performance of a newly developed integrant of Zymomonas mobilis for ethanol production on corn stover hydrolysate

Cited by 77 publications

References 11 publications

Progress and perspective on lignocellulosic hydrolysate inhibitor tolerance improvement in Zymomonas mobilis

Progress and perspective on lignocellulosic hydrolysate inhibitor tolerance improvement in Zymomonas mobilis

Construction of an Escherichia coli K-12 Mutant for Homoethanologenic Fermentation of Glucose or Xylose without Foreign Genes

Impact of recycling stillage on conversion of dilute sulfuric acid pretreated corn stover to ethanol

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