Comparison of glucose/xylose co-fermentation by recombinant Zymomonas mobilis under different genetic and environmental conditions

Ma, Yuanyuan; Dong, Huina; Zou, Shaolan; Hong, Jiefang; Zhang, Minhua

doi:10.1007/s10529-012-0897-4

Cited by 15 publications

(6 citation statements)

References 15 publications

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“…Since then, recombinant and evolved Z. mobilis strains for xylose and arabinose utilization have been developed through metabolic engineering and adaptation or similar methods. Importantly, some recombinant strains of Z. mobilis have been improved to utilize glucose, xylose and arabinose derived from lignocellulosic feedstock simultaneously for the fermentation of bioethanol (Chou et al ., ; Deanda et al ., ; Mohagheghi et al ., , ; Jeon et al ., ; Agrawal et al ., ; Ma et al ., ; Yanase et al ., ; Zhang et al ., ; Dunn and Rao, ; Wang et al ., ).…”

Section: Substrate Utilizationmentioning

confidence: 99%

Zymomonas mobilis as a model system for production of biofuels and biochemicals

Yang

Fei

Zhang

et al. 2016

Microbial Biotechnology

172

110

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Summary Zymomonas mobilis is a natural ethanologen with many desirable industrial biocatalyst characteristics. In this review, we will discuss work to develop Z. mobilis as a model system for biofuel production from the perspectives of substrate utilization, development for industrial robustness, potential product spectrum, strain evaluation and fermentation strategies. This review also encompasses perspectives related to classical genetic tools and emerging technologies in this context.

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Section: Substrate Utilizationmentioning

confidence: 99%

Zymomonas mobilis as a model system for production of biofuels and biochemicals

Yang

Fei

Zhang

et al. 2016

Microbial Biotechnology

172

110

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“…The pZ-XXTT2 plasmid contains foreign xylose metabolism genes encoding XI (xylose isomerase), XK (xylulokinase), TAL (transaldolase) and TKT (transketolase). The strain engineered by our laboratory [18] is capable of cofermenting the glucose and xylose present in the RM medium (20 g/L xylose, 10 g/L yeast extract, 2 g/L KH 2 PO 4 and 15 mg/L tetracycline) to ethanol.…”

Section: Microorganismsmentioning

confidence: 99%

Optimization of a synthetic medium for ethanol production by xylose-fermenting Zymomonas mobilis using response surface methodology

Dong

Zhao

et al. 2012

Chin. Sci. Bull.

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A synthetic medium for ethanol production by recombinant xylose-fermenting Zymomonas mobilis was optimized using Plackett-Burman (PB) design and response surface methodology (RSM). The effects of 19 medium components were investigated by PB design. Eight of these components were determined to have significant effects on ethanol production. The statistical model was constructed via central composite design (CCD) using five selected variables, including xylose, trisodium citrate, choline chloride, pyridoxine, and thiamine. The validity of the developed model was verified. The ethanol concentration in the optimized medium was 6.7% higher than in the RM medium. The optimized medium was then simplified to give the final synthetic medium (S2), in which the ethanol concentration was 20.7% higher than in the RM medium. Xylose and trisodium citrate were the key medium components influencing ethanol production, while calcium pantothenate was the only growth factor required by recombinant Z. mobilis. Ethanol production and growth response were directly proportional to the logarithm of the concentration of trisodium citrate in the range of 0.1-1.6 g/L.recombinant Zymomonas mobilis, synthetic medium, ethanol production, response surface methodology, trisodium citrate, xylose Citation:Dong H N, Zhao X M, Ma Y Y, et al. Optimization of a synthetic medium for ethanol production by xylose-fermenting Zymomonas mobilis using response surface methodology.

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“…Despite advances in engineering strains of Z. mobilis for pentose utilization [ 23 , 26 - 28 ], co-utilization of glucose and pentoses remains problematic, especially in the presence of inhibitory compounds such as acetate and furfural, and more work will be needed to achieve the high overall ethanol yields required for a commercial process [ 29 - 33 ] . Furthermore, despite recent systems biology studies undertaken to unravel the inhibitor tolerance mechanism of Z. mobilis for end-product ethanol [ 15 , 34 ], the single inhibitor acetate [ 35 , 36 ] or furfural [ 37 ], as well as the comprehensive hydrolysate toxic compounds [ 24 ], no transcriptomic study has yet been conducted focusing on the effect and interaction of pretreatment inhibitors and carbon source.…”

Section: Introductionmentioning

confidence: 99%

Insights into acetate toxicity in Zymomonas mobilis8b using different substrates

Yang

Franden

Brown

et al. 2014

Biotechnol Biofuels

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BackgroundLignocellulosic biomass is a promising renewable feedstock for biofuel production. Acetate is one of the major inhibitors liberated from hemicelluloses during hydrolysis. An understanding of the toxic effects of acetate on the fermentation microorganism and the efficient utilization of mixed sugars of glucose and xylose in the presence of hydrolysate inhibitors is crucial for economic biofuel production.ResultsA new microarray was designed including both coding sequences and intergenic regions to investigate the acetate stress responses of Zymomonas mobilis 8b when using single carbon sources of glucose or xylose, or mixed sugars of both glucose and xylose. With the supplementation of exogenous acetate, 8b can utilize all the glucose with a similar ethanol yield, although the growth, final biomass, and ethanol production rate were reduced. However, xylose utilization was inhibited in both media containing xylose or a mixed sugar of glucose and xylose, although the performance of 8b was better in mixed sugar than xylose-only media. The presence of acetate caused genes related to biosynthesis, the flagellar system, and glycolysis to be downregulated, and genes related to stress responses and energy metabolism to be upregulated. Unexpectedly, xylose seems to pose more stress on 8b, recruiting more genes for xylose utilization, than does acetate. Several gene candidates based on transcriptome results were selected for genetic manipulation, and a TonB-dependent receptor knockout mutant was confirmed to have a slight advantage regarding acetate tolerance.ConclusionsOur results indicate Z. mobilis utilized a different mechanism for xylose utilization, with an even more severe impact on Z. mobilis than that caused by acetate treatment. Our study also suggests redox imbalance caused by stressful conditions may trigger a metabolic reaction leading to the accumulation of toxic intermediates such as xylitol, but Z. mobilis manages its carbon and energy metabolism through the control of individual reactions to mitigate the stressful conditions. We have thus provided extensive transcriptomic datasets and gained insights into the molecular responses of Z. mobilis to the inhibitor acetate when grown in different sugar sources, which will facilitate future metabolic modeling studies and strain improvement efforts for better xylose utilization and acetate tolerance.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-014-0140-8) contains supplementary material, which is available to authorized users.

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Comparison of glucose/xylose co-fermentation by recombinant Zymomonas mobilis under different genetic and environmental conditions

Cited by 15 publications

References 15 publications

Zymomonas mobilis as a model system for production of biofuels and biochemicals

Zymomonas mobilis as a model system for production of biofuels and biochemicals

Optimization of a synthetic medium for ethanol production by xylose-fermenting Zymomonas mobilis using response surface methodology

Insights into acetate toxicity in Zymomonas mobilis8b using different substrates

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