Effects of overexpression of acetaldehyde dehydrogenase 6 and acetyl-CoA synthetase 1 on xylitol production in recombinant Saccharomyces cerevisiae

Oh, Eun‐Suok; Bae, Yi-Hyun; Kim, Kyoung Heon; Park, Yong Cheol; Seo, Jin Ho

doi:10.1016/j.bcab.2011.08.011

Cited by 26 publications

(6 citation statements)

References 18 publications

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“…Specific rates of glucose consumption and ethanol formation ( q : mmol∙h −1 ∙g −1 of dry biomass) in the exponential growth phase were calculated from three independent experiments. Dry cell weight (DCW) was estimated by multiplying optical density value and a conversion factor (0.3) together 51 .…”

Section: Methodsmentioning

confidence: 99%

GSF2 deletion increases lactic acid production by alleviating glucose repression in Saccharomyces cerevisiae

Baek

Kwon

Kim

et al. 2016

Sci Rep

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Improving lactic acid (LA) tolerance is important for cost-effective microbial production of LA under acidic fermentation conditions. Previously, we generated LA-tolerant D-LA-producing S. cerevisiae strain JHY5310 by laboratory adaptive evolution of JHY5210. In this study, we performed whole genome sequencing of JHY5310, identifying four loss-of-function mutations in GSF2, SYN8, STM1, and SIF2 genes, which are responsible for the LA tolerance of JHY5310. Among the mutations, a nonsense mutation in GSF2 was identified as the major contributor to the improved LA tolerance and LA production in JHY5310. Deletion of GSF2 in the parental strain JHY5210 significantly improved glucose uptake and D-LA production levels, while derepressing glucose-repressed genes including genes involved in the respiratory pathway. Therefore, more efficient generation of ATP and NAD+ via respiration might rescue the growth defects of the LA-producing strain, where ATP depletion through extensive export of lactate and proton is one of major reasons for the impaired growth. Accordingly, alleviation of glucose repression by deleting MIG1 or HXK2 in JHY5210 also improved D-LA production. GSF2 deletion could be applied to various bioprocesses where increasing biomass yield or respiratory flux is desirable.

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Section: Methodsmentioning

confidence: 99%

GSF2 deletion increases lactic acid production by alleviating glucose repression in Saccharomyces cerevisiae

Baek

Kwon

Kim

et al. 2016

Sci Rep

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“…ACS has been a target in multiple metabolic engineering strategies with S. cerevisiae for overproduction of acetyl-CoA-derived products (40)(41)(42), as well as for overproduction of NADPH for aerobic xylitol production (43). We chose to overexpress ACS2, which unlike ACS1 is not subject to glucose catabolite inactivation (44).…”

Section: Construction Of a Gpdmentioning

confidence: 99%

Increasing Anaerobic Acetate Consumption and Ethanol Yields in Saccharomyces cerevisiae with NADPH-Specific Alcohol Dehydrogenase

Henningsen

Hon

Covalla

et al. 2015

Appl Environ Microbiol

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Saccharomyces cerevisiae has recently been engineered to use acetate, a primary inhibitor in lignocellulosic hydrolysates, as a cosubstrate during anaerobic ethanolic fermentation. However, the original metabolic pathway devised to convert acetate to ethanol uses NADH-specific acetylating acetaldehyde dehydrogenase and alcohol dehydrogenase and quickly becomes constrained by limited NADH availability, even when glycerol formation is abolished. We present alcohol dehydrogenase as a novel target for anaerobic redox engineering of S. cerevisiae. Introduction of an NADPH-specific alcohol dehydrogenase (NADPH-ADH) not only reduces the NADH demand of the acetate-to-ethanol pathway but also allows the cell to effectively exchange NADPH for NADH during sugar fermentation. Unlike NADH, NADPH can be freely generated under anoxic conditions, via the oxidative pentose phosphate pathway. We show that an industrial bioethanol strain engineered with the original pathway (expressing acetylating acetaldehyde dehydrogenase from Bifidobacterium adolescentis and with deletions of glycerol-3-phosphate dehydrogenase genes GPD1 and GPD2) consumed 1.9 g liter ؊1 acetate during fermentation of 114 g liter ؊1 glucose. Combined with a decrease in glycerol production from 4.0 to 0.1 g liter ؊1 , this increased the ethanol yield by 4% over that for the wild type. We provide evidence that acetate consumption in this strain is indeed limited by NADH availability. By introducing an NADPH-ADH from Entamoeba histolytica and with overexpression of ACS2 and ZWF1, we increased acetate consumption to 5.3 g liter ؊1and raised the ethanol yield to 7% above the wild-type level. Saccharomyces cerevisiae is the principal microorganism used to produce ethanol, of which 93 billion liters were globally produced in 2014 (1). However, new strains are needed for the production of second-generation biofuels. Pretreatment and monomerization of lignocellulosic substrates produce complex sugar mixtures, including the C 5 sugars xylose and arabinose that are poorly fermented by most wild-type S. cerevisiae strains (2, 3). In addition, a variety of inhibitory compounds are released, such as furfural, hydroxymethylfurfural, methylglyoxal, and acetate (4-6). It is therefore desirable not only to expand the substrate range of S. cerevisiae (3, 7-9) but also to increase its inhibitor tolerance (10-13).Acetate is released during deacylation of hemicellulose and lignin and can be present in concentrations of Ͼ10 g liter Ϫ1 in cellulosic hydrolysates (4,14). At low pH particularly, this weak organic acid is a potent inhibitor of S. cerevisiae metabolism (15-17). Unfortunately, wild-type S. cerevisiae strains are poorly equipped to eliminate acetate from the medium under anoxic conditions. S. cerevisiae can grow on acetate as the sole carbon source under oxic conditions by converting acetate to acetyl coenzyme A (acetyl-CoA) with acetyl-CoA synthetase (ACS) (EC 6.2.1.1) and by either respiring acetyl-CoA in the tricarboxylic acid (TCA) cycle or upgrading acetyl-CoA to four-...

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“…Acetyl‐CoA synthetase (Acs1p) converts acetate to acetyl‐CoA, which is metabolized further into the tricarboxylic acid cycle with the NADH and NADPH regeneration metabolism. Since acetate is produced from acetaldehyde by NADPH regeneration, overexpression of acetyl‐CoA synthetase is expected to modulate both NADH and NADPH levels simultaneously and indirectly [24]. Overexpression of Zwf1p and Acs1p enhanced the intracellular pools of NADPH and NADH (Supporting information, Table S3), resulting in maximum 17% increases in xylitol productivity than the control strain (Supporting information, Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Coexpression of glucose‐6‐phosphate dehydrogenase and 6‐phosphogluconate dehydrogenase, two main NADPH‐regenerating enzymes, increased xylitol productivity by engineered Candida tropicalis PP [30]. Coexpression of Acs1p and NADP + ‐dependent aldehyde dehydrogenase 6 (Ald6p) in engineered S. cerevisiae BJ3505:δXR exerted a negative effect on xylitol production, compared to their single expression [24]. As shown in Fig.…”

Section: Discussionmentioning

confidence: 99%

Dual utilization of NADPH and NADH cofactors enhances xylitol production in engineered Saccharomyces cerevisiae

Lee

et al. 2015

Biotechnology Journal

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Xylitol, a natural sweetener, can be produced by hydrogenation of xylose in hemicelluloses. In microbial processes, utilization of only NADPH cofactor limited commercialization of xylitol biosynthesis. To overcome this drawback, Saccharomyces cerevisiae D452-2 was engineered to express two types of xylose reductase (XR) with either NADPH-dependence or NADH-preference. Engineered S. cerevisiae DWM expressing both the XRs exhibited higher xylitol productivity than the yeast strain expressing NADPH-dependent XR only (DWW) in both batch and glucose-limited fed-batch cultures. Furthermore, the coexpression of S. cerevisiae ZWF1 and ACS1 genes in the DWM strain increased intracellular concentrations of NADPH and NADH and improved maximum xylitol productivity by 17%, relative to that for the DWM strain. Finally, the optimized fed-batch fermentation of S. cerevisiae DWM-ZWF1-ACS1 resulted in 196.2 g/L xylitol concentration, 4.27 g/L h productivity and almost the theoretical yield. Expression of the two types of XR utilizing both NADPH and NADH is a promising strategy to meet the industrial demands for microbial xylitol production.

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Effects of overexpression of acetaldehyde dehydrogenase 6 and acetyl-CoA synthetase 1 on xylitol production in recombinant Saccharomyces cerevisiae

Cited by 26 publications

References 18 publications

GSF2 deletion increases lactic acid production by alleviating glucose repression in Saccharomyces cerevisiae

GSF2 deletion increases lactic acid production by alleviating glucose repression in Saccharomyces cerevisiae

Increasing Anaerobic Acetate Consumption and Ethanol Yields in Saccharomyces cerevisiae with NADPH-Specific Alcohol Dehydrogenase

Dual utilization of NADPH and NADH cofactors enhances xylitol production in engineered Saccharomyces cerevisiae

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