Betaine supplementation improved l-threonine fermentation of Escherichia coli THRD by upregulating zwf (glucose-6-phosphate dehydrogenase) expression

Li, Yanjun; Zhang, Dezhi; Cai, Ningyun; Han, Chao; Mao, Qiang; Wang, Ting; Zhou, Qian; Chen, Ning; Xie, Xiulan

doi:10.1016/j.ejbt.2019.03.004

Cited by 11 publications

(12 citation statements)

References 26 publications

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“…The current research on the fermentation process mainly focuses on betaine addition. After 24 h fermentation supplemented with betaine l -threonine titer increased 13.3% in E. coli THRD [ 3 ]. As for the mechanism of adding betaine to improve the fermentation properties of strains, betaine increases the transcription level of the zwf encoding glucose-6-phosphate dehydrogenase [ 3 ].…”

Section: Discussionmentioning

confidence: 99%

“…After 24 h fermentation supplemented with betaine l -threonine titer increased 13.3% in E. coli THRD [ 3 ]. As for the mechanism of adding betaine to improve the fermentation properties of strains, betaine increases the transcription level of the zwf encoding glucose-6-phosphate dehydrogenase [ 3 ]. Addition of betaine can protect the protein activity in the cell when the environmental osmotic pressure rises [ 29 , 30 ] and maintains the ion balance inside and outside the cell [ 31 ].…”

Section: Discussionmentioning

confidence: 99%

“…The resulting recombinant strain produced 33 g/l l -threonine when grown under open unsterile conditions with a productivity of 1.368 g/l/h in fed-batch fermentation [ 2 ]. Osmoprotectants have been used to improve the growth and yield limitations caused by the imbalance of osmotic pressure during the fermentation process [ 3 , 4 ]. Betaine has been applied as one of the osmoprotectants due to its special methylation-related structure [ 3 , 5 , 6 ].…”

Section: Introductionmentioning

confidence: 99%

“…Osmoprotectants have been used to improve the growth and yield limitations caused by the imbalance of osmotic pressure during the fermentation process [ 3 , 4 ]. Betaine has been applied as one of the osmoprotectants due to its special methylation-related structure [ 3 , 5 , 6 ]. In E. coli , betaine plays an indispensable role in cell growth and production of target metabolites [ 5 ].…”

Section: Introductionmentioning

confidence: 99%

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Improving l-threonine production in Escherichia coli by elimination of transporters ProP and ProVWX

et al. 2021

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Background Betaine, an osmoprotective compatible solute, has been used to improve l-threonine production in engineered Escherichia colil-threonine producer. Betaine supplementation upregulates the expression of zwf encoding glucose-6-phosphate dehydrogenase, leading to the increase of NADPH, which is beneficial for l-threonine production. In E. coli, betaine can be taken through ProP encoded by proP or ProVWX encoded by proVWX. ProP is a H+-osmolyte symporter, whereas ProVWX is an ABC transporter. ProP and ProVWX mediate osmotic stress protection by transporting zwitterionic osmolytes, including glycine betaine. Betaine can also be synthesized in E. coli by enzymes encoded by betABIT. However, the influence of ProP, ProVWX and betABIT on l-threonine production in E. coli has not been investigated. Results In this study, the influence of ProP, ProVWX and betABIT on l-threonine production in E. coli has been investigated. Addition of betaine slightly improved the growth of the l-threonine producing E. coli strain TWF001 as well as the l-threonine production. Deletion of betABIT retarded the growth of TWF001 and slightly decreased the l-threonine production. However, deletion of proP or/and proVWX significantly increased the l-threonine production. When proP was deleted, the l-threonine production increased 33.3%; when proVWX was deleted, the l-threonine production increased 40.0%. When both proP and proVWX were deleted, the resulting strain TSW003 produced 23.5 g/l l-threonine after 36 h flask cultivation. The genes betABIT, proC, fadR, crr and ptsG were individually deleted from TSW003, and it was found that further absence of either crr (TWS008) or ptsG (TWS009) improved l-threonine production. TSW008 produced 24.9 g/l l-threonine after 36 h flask cultivation with a yield of 0.62 g/g glucose and a productivity of 0.69 g/l/h. TSW009 produced 26 g/l l-threonine after 48 h flask cultivation with a yield of 0.65 g/g glucose and a productivity of 0.54 g/l/h, which is 116% increase compared to the control TWF001. Conclusions In this study, l-threonine-producing E. coli strains TSW008 and TSW009 with high l-threonine productivity were developed by regulating the intracellular osmotic pressure. This strategy could be used to improve the production of other products in microorganisms.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Improving l-threonine production in Escherichia coli by elimination of transporters ProP and ProVWX

et al. 2021

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“…In E. coli, NADPH is mostly produced in the pentose phosphate pathway by glucose-6-phosphate dehydrogenase encoded by the gene zwf, which catalyzes the oxidation of glucose 6-phosphate to 6-phosphoglucono-δ-lactone; 6-phosphogluconate dehydrogenase encoded by the genes gnd could also produce NADPH through the oxidative decarboxylation of 6-phosphogluconate to ribulose 5-phosphate [73]. Several approaches to increase the NADPH yield through metabolic engineering of genes involved in the pentose phosphate pathway have been reported [74][75][76][77][78][79][80]. Therefore, it is worth studying the influence of NADPH on l-threonine production in TWF083.…”

Section: Discussionmentioning

confidence: 99%

Expression regulation of multiple key genes to improve l-threonine in Escherichia coli

Zhao

Yang

et al. 2020

Microb Cell Fact

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Background: Escherichia coli is an important strain for l-threonine production. Genetic switch is a ubiquitous regulatory tool for gene expression in prokaryotic cells. To sense and regulate intracellular or extracellular chemicals, bacteria evolve a variety of transcription factors. The key enzymes required for l-threonine biosynthesis in E. coli are encoded by the thr operon. The thr operon could coordinate expression of these genes when l-threonine is in short supply in the cell. Results: The thrL leader regulatory elements were applied to regulate the expression of genes iclR, arcA, cpxR, gadE, fadR and pykF, while the threonine-activating promoters P cysH , P cysJ and P cysD were applied to regulate the expression of gene aspC, resulting in the increase of l-threonine production in an l-threonine producing E. coli strain TWF001. Firstly, different parts of the regulator thrL were inserted in the iclR regulator region in TWF001, and the best resulting strain TWF063 produced 16.34 g l-threonine from 40 g glucose after 30 h cultivation. Secondly, the gene aspC following different threonine-activating promoters was inserted into the chromosome of TWF063, and the best resulting strain TWF066 produced 17.56 g l-threonine from 40 g glucose after 30 h cultivation. Thirdly, the effect of expression regulation of arcA, cpxR, gadE, pykF and fadR was individually investigated on l-threonine production in TWF001. Finally, using TWF066 as the starting strain, the expression of genes arcA, cpxR, gadE, pykF and fadR was regulated individually or in combination to obtain the best strain for l-threonine production. The resulting strain TWF083, in which the expression of seven genes (iclR, aspC, arcA, cpxR, gadE, pykF, fadR and aspC) was regulated, produced 18.76 g l-threonine from 30 g glucose, 26.50 g l-threonine from 40 g glucose, or 26.93 g l-threonine from 50 g glucose after 30 h cultivation. In 48 h fed-batch fermentation, TWF083 could produce 116.62 g/L l-threonine with a yield of 0.486 g/g glucose and productivity of 2.43 g/L/h. Conclusion: The genetic engineering through the expression regulation of key genes is a better strategy than simple deletion of these genes to improve l-threonine production in E. coli. This strategy has little effect on the intracellular metabolism in the early stage of the growth but could increase l-threonine biosynthesis in the late stage.

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Advances in microbial production of feed amino acid

Zhao

Liu

Gao

et al. 2022

Advances in Applied Microbiology

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Betaine supplementation improved l-threonine fermentation of Escherichia coli THRD by upregulating zwf (glucose-6-phosphate dehydrogenase) expression

Cited by 11 publications

References 26 publications

Improving l-threonine production in Escherichia coli by elimination of transporters ProP and ProVWX

Improving l-threonine production in Escherichia coli by elimination of transporters ProP and ProVWX

Expression regulation of multiple key genes to improve l-threonine in Escherichia coli

Advances in microbial production of feed amino acid

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