Two-stage transcriptional reprogramming in Saccharomyces cerevisiae for optimizing ethanol production from xylose

Cao, Limin; Tang, Xingliang; Zhang, Xinyuan; Zhang, Jingtao; Tian, Xue-Lei; Wang, Jingyu; Xiong, Mei; Xiao, Wei

doi:10.1016/j.ymben.2014.05.001

Cited by 42 publications

(51 citation statements)

References 29 publications

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“…Despite efforts to develop pentose-utilizing strains, pentose consumption by recombinant S. cerevisiae is still slower than glucose consumption (Oreb et al 2012). To tackle this obstacle, approaches including overexpression of transporter for pentose uptake (Farwick et al 2014;Goncalves et al 2014;Young et al 2014), evolutionary engineering of strains (Lee et al 2014;Smith et al 2014), and optimization of gene expression related to pentose metabolism (Cao et al 2014) have been employed, although to our best knowledge, none of the resultant strains exhibit efficient utilization of xylose at a level comparable to that of glucose. Another technological challenge for industrial production of cellulosic ethanol is the formation of inhibitory compounds, such as furans, aromatic compounds, and weak organic acids during the thermochemical treatment of lignocellulosic biomass, a pretreatment process that is required to enhance accessibility of biomass to saccharification enzymes.…”

Section: Introductionmentioning

confidence: 99%

Metabolic engineering for improved production of ethanol by Corynebacterium glutamicum

Jojima

Noburyu

Sasaki

et al. 2014

Appl Microbiol Biotechnol

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Recombinant Corynebacterium glutamicum harboring genes for pyruvate decarboxylase (pdc) and alcohol dehydrogenase (adhB) can produce ethanol under oxygen deprivation. We investigated the effects of elevating the expression levels of glycolytic genes, as well as pdc and adhB, on ethanol production. Overexpression of four glycolytic genes (pgi, pfkA, gapA, and pyk) in C. glutamicum significantly increased the rate of ethanol production. Overexpression of tpi, encoding triosephosphate isomerase, further enhanced productivity. Elevated expression of pdc and adhB increased ethanol yield, but not the rate of production. Fed-batch fermentation using an optimized strain resulted in ethanol production of 119 g/L from 245 g/L glucose with a yield of 95% of the theoretical maximum. Further metabolic engineering, including integration of the genes for xylose and arabinose metabolism, enabled consumption of glucose, xylose, and arabinose, and ethanol production (83 g/L) at a yield of 90 %. This study demonstrated that C. glutamicum has significant potential for the production of cellulosic ethanol.

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Section: Introductionmentioning

confidence: 99%

Metabolic engineering for improved production of ethanol by Corynebacterium glutamicum

Jojima

Noburyu

Sasaki

et al. 2014

Appl Microbiol Biotechnol

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“…Thus, improving import and the intracellular pentose utilization efficiency is very critical, and intensive efforts have been made to do so by yeast metabolic engineering (7)(8)(9)(10)(11)(12)(13). Sugar uptake is the initial step for its utilization, and therefore, efficient molecular transport is a prerequisite to achieve enhanced fermentation rates in the presence of a working pentose metabolism pathway.…”

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confidence: 99%

Functional Analysis of Two l -Arabinose Transporters from Filamentous Fungi Reveals Promising Characteristics for Improved Pentose Utilization in Saccharomyces cerevisiae

Cai

et al. 2015

Appl Environ Microbiol

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cLimited uptake is one of the bottlenecks for L-arabinose fermentation from lignocellulosic hydrolysates in engineered Saccharomyces cerevisiae. This study characterized two novel L-arabinose transporters, LAT-1 from Neurospora crassa and MtLAT-1 from Myceliophthora thermophila. Although the two proteins share high identity (about 83%), they display different substrate specificities. Sugar transport assays using the S. cerevisiae strain EBY.VW4000 indicated that LAT-1 accepts a broad substrate spectrum. In contrast, MtLAT-1 appeared much more specific for L-arabinose. Determination of the kinetic properties of both transporters revealed that the K m values of LAT-1 and MtLAT-1 for L-arabinose were 58.12 ؎ 4.06 mM and 29.39 ؎ 3.60 mM, respectively, with corresponding V max values of 116.7 ؎ 3.0 mmol/h/g dry cell weight (DCW) and 10.29 ؎ 0.35 mmol/h/g DCW, respectively. In addition, both transporters were found to use a proton-coupled symport mechanism and showed only partial inhibition by D-glucose during L-arabinose uptake. Moreover, LAT-1 and MtLAT-1 were expressed in the S. cerevisiae strain BSW2AP containing an L-arabinose metabolic pathway. Both recombinant strains exhibited much faster L-arabinose utilization, greater biomass accumulation, and higher ethanol production than the control strain. In conclusion, because of higher maximum velocities and reduced inhibition by D-glucose, the genes for the two characterized transporters are promising targets for improved L-arabinose utilization and fermentation in S. cerevisiae. Biorefining of lignocellulosic biomass has attracted considerable attention in recent years because of its abundance, sustainability and potential environmental benefits (1, 2). The main sugars in hydrolysates from currently used feedstocks are a mixture of D-glucose, D-xylose, and L-arabinose (3). For a cost-effective conversion of biomass into fuels or chemicals, the fermentative organisms are required to utilize all three sugars efficiently. Even though many organisms are able to natively convert these substrates, the most commonly selected microbe is Saccharomyces cerevisiae (baker's yeast) because of its high ethanol productivity and high tolerance for inhibitors present in biomass hydrolysates, as well as the fact that it is amenable to genetic engineering (4-6).Wild-type S. cerevisiae cannot utilize the two pentose sugars D-xylose and L-arabinose. Thus, improving import and the intracellular pentose utilization efficiency is very critical, and intensive efforts have been made to do so by yeast metabolic engineering (7-13). Sugar uptake is the initial step for its utilization, and therefore, efficient molecular transport is a prerequisite to achieve enhanced fermentation rates in the presence of a working pentose metabolism pathway. Baker's yeast is able to absorb pentoses through its native hexose transporters, such as Hxt5 and Hxt7, and the galactose transporter Gal2 (14-16). However, these transporters show higher affinity for hexoses, and thus, it was suggested that D-glucose impa...

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“…In most cases, the xylose consumption is inhibited by glucose during co-fermentation due to catabolite repression, which led to diauxic fermentation and reduced the efficiency. The reduced ethanol tolerance during xylose fermentation, which may be due to the cofactor preference of the oxidation-reduction cycle, became more severe after glucose was consumed and the ethanol was accumulated (Cao et al, 2014;Ha et al, 2011). A previous study reported that the xylose consumption in K. marxianus was inhibited by glucose and the KmXYL1 expression was very low even in mixed sugar (Rodrussamee et al, 2011).…”

Section: Tablementioning

confidence: 99%

Rapid ethanol production at elevated temperatures by engineered thermotolerant Kluyveromyces marxianus via the NADP(H)-preferring xylose reductase-xylitol dehydrogenase pathway

Jia

Zhang

Wang

et al. 2015

Metabolic Engineering

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Two-stage transcriptional reprogramming in Saccharomyces cerevisiae for optimizing ethanol production from xylose

Cited by 42 publications

References 29 publications

Metabolic engineering for improved production of ethanol by Corynebacterium glutamicum

Metabolic engineering for improved production of ethanol by Corynebacterium glutamicum

Functional Analysis of Two l -Arabinose Transporters from Filamentous Fungi Reveals Promising Characteristics for Improved Pentose Utilization in Saccharomyces cerevisiae

Rapid ethanol production at elevated temperatures by engineered thermotolerant Kluyveromyces marxianus via the NADP(H)-preferring xylose reductase-xylitol dehydrogenase pathway

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