Disruption of lactate dehydrogenase through homologous recombination to improve bioethanol production in Thermoanaerobacterium aotearoense

Cai, Youhua; Lai, Chaofeng; Li, Shuang; Liang, Zexin; Zhu, Ming‐Jun; Song, Liang; Wang, Jufang

doi:10.1016/j.enzmictec.2010.10.006

Cited by 34 publications

(21 citation statements)

References 35 publications

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“…Thermoanaerobacterium aotearoense SCUT27 was isolated from a hot spring in South China, and its optimal growth temperature was determined to be 55 °C . SCUT27 has all the advantages over mesophilic bacteria mentioned above.…”

Section: Introductionmentioning

confidence: 89%

Enhanced ethanol production from lignocellulosic hydrolysates by inhibiting the hydrogen synthesis in Thermoanaerobacterium aotearoense SCUT27(Δldh)

Yang

et al. 2019

J of Chemical Tech & Biotech

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BACKGROUND Thermophilic anaerobic bacteria have gained increased interest as a desirable biological catalyst for bioethanol production from lignocellulosic biomass. However, by‐products such as lactic acid, acetic acid and hydrogen (H2) not only lead to low ethanol yield but also increase the difficulty of ethanol purification. Considering that ethanol production is dependent on the supply of NADH, blocking or inhibiting lactic acid (by knocking out ldh) and H2 formation should be a reliable strategy to further increase the ethanol production. RESULTS Comparative genome analysis indicated that three hydrogenase gene clusters (hyd, ech and hfs) were identified in Thermoanaerobacterium aotearoense SCUT27, and they were proved to be related to H2 production by gene knockout. Deletion of hyd or ech in SCUT27(Δldh) showed a decrease in substrate consumption and ethanol production, while hfsB gene knockout resulted in significant improvement in overall fermentation performance. Compared with SCUT27(Δldh), the ethanol concentration, yield and productivity of SCUT27(Δldh/ΔhfsB) were increased from 25.15 ± 0.45 g L−1, 0.33 ± 0.01 g g−1 and 0.30 ± 0.01 g L−1 h−1 to 39.64 ± 0.16 g L−1, 0.36 ± 0.00 g g−1 and 0.41 ± 0.01 g L−1 h−1 respectively using glucose in fed‐batch fermentation. The enhanced ethanol production was due to the increased NADH supply and alcohol dehydrogenase activity. Finally, the feasibility of ethanol production by SCUT27(Δldh/ΔhfsB) from hydrolysates of soybean hull, wheat straw, corn cob and corn straw was demonstrated. CONCLUSION Knocking out the ldh and hfsB in SCUT27 is an efficient strategy for diverting carbon flux and NADH towards ethanol production, and the resulting strain SCUT27(Δldh/ΔhfsB) has great potential in the production of ethanol from lignocellulosic hydrolysates. © 2019 Society of Chemical Industry

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Section: Introductionmentioning

confidence: 89%

Enhanced ethanol production from lignocellulosic hydrolysates by inhibiting the hydrogen synthesis in Thermoanaerobacterium aotearoense SCUT27(Δldh)

Yang

et al. 2019

J of Chemical Tech & Biotech

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“…Thermoanaerobacterium aotearoense SCUT27, a Gram-positive, thermophilic, strict anaerobe recently isolated from a hot spring in China, has broad substrate specificity, including xylan, dextran (1), and various sugars, including glucose, cellobiose, xylose, mannose, galactose, and arabinose (2). It has been metabolically engineered and developed as a biocatalyst for the production of ethanol, hydrogen, and l -lactic acid (1–3).…”

Section: Genome Announcementmentioning

confidence: 99%

“…It has been metabolically engineered and developed as a biocatalyst for the production of ethanol, hydrogen, and l -lactic acid (1–3). In order to better understand the molecular mechanisms contributing to sugar utilization and ethanol production, we sequenced the genome of T. aotearoense SCUT27.…”

Section: Genome Announcementmentioning

confidence: 99%

Draft Genome Sequence of an Anaerobic, Thermophilic Bacterium, Thermoanaerobacterium aotearoense SCUT27, Isolated from a Hot Spring in China

Zhang

Yang

et al. 2014

Genome Announc

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Thermoanaerobacterium aotearoense SCUT27, isolated from a hot spring in China, is a strictly anaerobic, thermophilic bacterium capable of degrading xylan and converting both pentose and hexose to ethanol with high yields. Here, we report the draft genome sequence of SCUT27, which reveals insights into the mechanisms of carbon source coutilization and xylan degradation in this thermophilic microorganism.

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“…The obtained mutant strain exhibited 31.0% and 31.4% more microbial biomass and 2.37-(81.67 mM) and 2.1-fold (75 mM) increases in the yield of ethanol (mole/mole substrate) under glucose and xylose cultivation, respectively, compared to the wild type (32 mM ethanol). Moreover, no lactic acid was detected in Δldh mutant fermentation mixtures, whereas it was readily detected in the cultures of the wild type strain (Cai et al, 2011).…”

Section: Thermoanaerobacterium Aotearoensementioning

confidence: 99%

“…These disadvantages are caused by the many byproducts derived from the branch pathways including various organic acids, such as acetic and lactic acids, which in turn result in salt accumulation during pH-controlled fermentations, and consequent hindrance in ethanol production by these bacteria (Lynd et al, 2001(Lynd et al, , 2002Cai et al, 2011). So, engineering Thermoanaerobacterium species to overcome these problems could be a promising strategy to commercialize ethanol production by these organisms.…”

Section: Thermoanaerobacterium Saccharolyticummentioning

confidence: 99%

Advances in consolidated bioprocessing systems for bioethanol and butanol production from biomass: a comprehensive review

2015

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HIGHLIGHTS Various CBP strategies have been discussed. Recently, lignocellulosic biomass as the most abundant renewable resource has been widely considered for bioalcohols production. However, the complex structure of lignocelluloses requires a multi-step process which is costly and time consuming. Although, several bioprocessing approaches have been developed for pretreatment, saccharification and fermentation, bioalcohols production from lignocelluloses is still limited because of the economic infeasibility of these technologies. This cost constraint could be overcome by designing and constructing robust cellulolytic and bioalcohols producing microbes and by using them in a consolidated bioprocessing (CBP) system. This paper comprehensively reviews potentials, recent advances and challenges faced in CBP systems for efficient bioalcohols (ethanol and butanol) production from lignocellulosic and starchy biomass. The CBP strategies include using native single strains with cellulytic and alcohol production activities, microbial co-cultures containing both cellulytic and ethanologenic microorganisms, and genetic engineering of cellulytic microorganisms to be alcohol-producing or alcohol producing microorganisms to be cellulytic. Moreover, high-throughput techniques, such as metagenomics, metatranscriptomics, next generation sequencing and synthetic biology developed to explore novel microorganisms and powerful enzymes with high activity, thermostability and pH stability are also discussed. Currently, the CBP technology is in its infant stage, and ideal microorganisms and/or conditions at industrial scale are yet to be introduced. So, it is essential to bring into attention all barriers faced and take advantage of all the experiences gained to achieve a high-yield and low-cost CBP process.

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Disruption of lactate dehydrogenase through homologous recombination to improve bioethanol production in Thermoanaerobacterium aotearoense

Cited by 34 publications

References 35 publications

Enhanced ethanol production from lignocellulosic hydrolysates by inhibiting the hydrogen synthesis in Thermoanaerobacterium aotearoense SCUT27(Δldh)

Enhanced ethanol production from lignocellulosic hydrolysates by inhibiting the hydrogen synthesis in Thermoanaerobacterium aotearoense SCUT27(Δldh)

Draft Genome Sequence of an Anaerobic, Thermophilic Bacterium, Thermoanaerobacterium aotearoense SCUT27, Isolated from a Hot Spring in China

Advances in consolidated bioprocessing systems for bioethanol and butanol production from biomass: a comprehensive review

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