Carbon catabolite repression relaxation in Escherichia coli: global and sugar-specific methods for glucose and secondary sugar co-utilization

Fox, Kevin J; Prather, Kristala L. J.

doi:10.1016/j.coche.2020.05.005

Cited by 30 publications

(19 citation statements)

References 48 publications

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“…By this way, researchers have successfully built Gal2-N376F, CiGXS1 FIVFH497* and AN25-R4.18 [ 6 – 8 ]. In addition, adaptive evolution, computation simulation, and rational design have been used to find appropriate intracellular targets to alleviate CCR, such as the phosphoenolpyruvate transferase system (PTS), the cyclic AMP receptor protein (CRP), and the xylose operon regulatory protein [ 9 , 10 ]. However, the complex nature of CCR makes it difficult to entirely reveal how CCR functions.…”

Section: Introductionmentioning

confidence: 99%

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Cellulosic ethanol production by consortia of Scheffersomyces stipitis and engineered Zymomonas mobilis

Sun

Zhang

et al. 2021

Biotechnol Biofuels

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Background As one of the clean and sustainable energies, lignocellulosic ethanol has achieved much attention around the world. The production of lignocellulosic ethanol does not compete with people for food, while the consumption of ethanol could contribute to the carbon dioxide emission reduction. However, the simultaneous transformation of glucose and xylose to ethanol is one of the key technologies for attaining cost-efficient lignocellulosic ethanol production at an industrial scale. Genetic modification of strains and constructing consortia were two approaches to resolve this issue. Compared with strain improvement, the synergistic interaction of consortia in metabolic pathways should be more useful than using each one separately. Results In this study, the consortia consisting of suspended Scheffersomyces stipitis CICC1960 and Zymomonas mobilis 8b were cultivated to successfully depress carbon catabolite repression (CCR) in artificially simulated 80G40XRM. With this strategy, a 5.52% more xylose consumption and a 6.52% higher ethanol titer were achieved by the consortium, in which the inoculation ratio between S. stipitis and Z. mobilis was 1:3, compared with the Z. mobilis 8b mono-fermentation. Subsequently, one copy of the xylose metabolic genes was inserted into the Z. mobilis 8b genome to construct Z. mobilis FR2, leading to the xylose final-consumption amount and ethanol titer improvement by 15.36% and 6.81%, respectively. Finally, various corn stover hydrolysates with different sugar concentrations (glucose and xylose 60, 90, 120 g/L), were used to evaluate the fermentation performance of the consortium consisting of S. stipitis CICC1960 and Z. mobilis FR2. Fermentation results showed that a 1.56–4.59% higher ethanol titer was achieved by the consortium compared with the Z. mobilis FR2 mono-fermentation, and a 46.12–102.14% higher ethanol titer was observed in the consortium fermentation when compared with the S. stipitis CICC1960 mono-fermentation. Furthermore, qRT-PCR analysis of xylose/glucose transporter and other genes responsible for CCR explained the reason why the initial ratio inoculation of 1:3 in artificially simulated 80G40XRM had the best fermentation performance in the consortium. Conclusions The fermentation strategy used in this study, i.e., using a genetically modified consortium, had a superior performance in ethanol production, as compared with the S. stipitis CICC1960 mono-fermentation and the Z. mobilis FR2 mono-fermentation alone. This result showed that this strategy has potential for future lignocellulosic ethanol production.

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Section: Introductionmentioning

confidence: 99%

“…However, the complex nature of CCR makes it difficult to entirely reveal how CCR functions. Moreover, those above engineered strains developed cannot co-utilize glucose and xylose with high efficiency [ 9 ].…”

Section: Introductionmentioning

confidence: 99%

Cellulosic ethanol production by consortia of Scheffersomyces stipitis and engineered Zymomonas mobilis

Sun

Zhang

et al. 2021

Biotechnol Biofuels

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show abstract

“…By this way, researchers have successfully built Gal2-N376F, CiGXS1 FIVFH497* and AN25-R4.18 (6-8). In addition, adaptive evolution, computation simulation, and rational design have been used to nd appropriate intracellular targets to alleviate CCR, such as the phosphoenolpyruvate transferase system (PTS), the cyclic AMP receptor protein (CRP), and the xylose operon regulatory protein (9,10). However, the complex nature of CCR makes it di cult for us to entirely unveil how CCR functions.…”

Section: Introductionmentioning

confidence: 99%

“…However, the complex nature of CCR makes it di cult for us to entirely unveil how CCR functions. Moreover, those engineered strains developed by the abovementioned methods typically cannot co-utilize glucose and xylose with high e ciency (9). An alternative method is to build arti cial consortia to co-ferment glucose and xylose.…”

Section: Introductionmentioning

confidence: 99%

“…An alternative method is to build arti cial consortia to co-ferment glucose and xylose. A common practice is to build a consortium consisting of a xylose-speci c strain due to the de ciency in the PTS system and a wild strain that utilizes glucose because of CCR (9). In this way, for instance, 20.82 g/L butanol with a yield of 0.35 g/g was produced from glucose and xylose using two E. coli strains.…”

Section: Introductionmentioning

confidence: 99%

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Cellulosic Ethanol Production by Engineered Consortia of Scheffersomyces Stipitis and Zymomonas Mobilis

Sun

Zhang

et al. 2021

Preprint

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Background: As one of the clean and sustainable energies, lignocellulosic ethanol has achieved much attention around the world. The production of lignocellulosic ethanol does not compete with people for food, while the consumption of ethanol could contribute to the carbon dioxide emission reduction. Two of the conditions that are needed to attain cost-efficient lignocellulosic ethanol production at an industrial scale are the simultaneous transformation of glucose and xylose to ethanol and a highly efficient ethanol fermentation process. Results: In this study, the consortia consisting of suspended Scheffersomyces stipitis CICC1960 and Zymomonas mobilis 8b were cultivated to successfully depress carbon catabolite repression (CCR) in 80G40XRM. With this strategy, a 5.52% more xylose consumption and a 6.52% higher ethanol titer were achieved by the consortium, in which the inoculation ratio between S. stipitis and Z. mobilis was 1:3, at the end of fermentation compared with the Z. mobilis 8b mono-fermentation. Subsequently, one copy of the xylose metabolic genes was inserted into the Z. mobilis 8b genome to construct Z. mobilis FR2, leading to the xylose final-consumption amount and ethanol titer improvement by 15.36% and 6.81%, respectively. Finally, various concentrations of corn stover hydrolysates, in which the sum of glucose and xylose concentrations in the hydrolysates were 60, 90, and 120 g/L respectively, were used to evaluate the fermentation performance of the consortium consisting of S. stipitis CICC1960 and Z. mobilis FR2. Fermentation results showed that a 1.56% - 4.59% higher ethanol titer was achieved by the consortium compared with the Z. mobilis FR2 mono-fermentation, and a 46.12% - 102.14% higher ethanol titer was observed in the consortium fermentation when compared with the S. stipitis CICC1960 mono-fermentation. Conclusions: The fermentation strategy used in this study, i.e., using a genetically modified consortium, had a superior performance in ethanol production, as compared with the S. stipitis CICC1960 mono-fermentation and the Z. mobilis FR2 mono-fermentation alone. Thus, this strategy has potential for future lignocellulosic ethanol production.

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Intelligent self‐control of carbon metabolic flux in SecY‐engineered Escherichia coli for xylitol biosynthesis from xylose‐glucose mixtures

Guo

Ullah

Zheng

et al. 2021

Biotech & Bioengineering

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Xylitol is a salutary sugar substitute that has been widely used in the food, pharmaceutical, and chemical industries. Co-fermentation of xylose and glucose by metabolically engineered cell factories is a promising alternative to chemical hydrogenation of xylose for commercial production of xylitol. Here, we engineered a mutant of SecY proteintranslocation channel (SecY [ΔP]) in xylitol-producing Escherichia coli JM109 (DE3) as a passageway for xylose uptake. It was found that SecY (ΔP) channel could rapidly transport xylose without being interfered by XylB-catalyzed synthesis of xylitol-phosphate, which is impossible for native XylFGH and XylE transporters. More importantly, with the coaction of SecY (ΔP) channel and carbon catabolite repression (CCR), the flux of xylose to the pentose phosphate (PP) pathway and the xylitol synthesis pathway in E. coli could be automatically controlled in response to glucose, thereby ensuring that the mutant cells were able to fully utilize sugars with high xylitol yields. The E. coli cell factory developed in this study has been proven to be applicable to a broad range of xylose-glucose mixtures, which is conducive to simplifying the mixed-sugar fermentation process for efficient and economical production of xylitol.

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Carbon catabolite repression relaxation in Escherichia coli: global and sugar-specific methods for glucose and secondary sugar co-utilization

Cited by 30 publications

References 48 publications

Cellulosic ethanol production by consortia of Scheffersomyces stipitis and engineered Zymomonas mobilis

Cellulosic ethanol production by consortia of Scheffersomyces stipitis and engineered Zymomonas mobilis

Cellulosic Ethanol Production by Engineered Consortia of Scheffersomyces Stipitis and Zymomonas Mobilis

Intelligent self‐control of carbon metabolic flux in SecY‐engineered Escherichia coli for xylitol biosynthesis from xylose‐glucose mixtures

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