Increasing l-isoleucine production in Corynebacterium glutamicum by overexpressing global regulator Lrp and two-component export system BrnFE

Authors

  • L. Yin,

    1. State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China
    2. Key Laboratory of Industrial Biotechnology of Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
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  • F. Shi,

    1. State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China
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  • X. Hu,

    1. State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China
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  • C. Chen,

    1. Key Laboratory of Industrial Biotechnology of Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
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  • X. Wang

    Corresponding author
    1. Key Laboratory of Industrial Biotechnology of Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
    • State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China
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Correspondence

Prof. Xiaoyuan Wang, Jiangnan University, 1800 Lihu Avenue, Wuxi 214000, China. E-mail: xiaoyuanwang@hotmail.com

Abstract

Aims

To increase the l-isoleucine production in Corynebacterium glutamicum by overexpressing the global regulator Lrp and the two-component export system BrnFE.

Methods and Results

The brnFE operon and the lrp gene were cloned into the shuttle vector pDXW-8 individually or in combination. The constructed plasmids were transformed into an l-isoleucine-producing strain C. glutamicum JHI3-156, and the l-isoleucine production in these different strains was analysed and compared. More l-isoleucine was produced when only Lrp was expressed than when only BrnFE was expressed. Significant increase in l-isoleucine production was observed when Lrp and BrnFE were expressed in combination. Compared to the control strain, l-isoleucine production in JHI3-156/pDXW-8-lrp-brnFE increased 63% in flask cultivation, and the specific yield of l-isoleucine increased 72% in fed-batch fermentation.

Conclusions

Both Lrp and BrnFE are important to enhance the l-isoleucine production in C. glutamicum.

Significance and Impact of the Study

The results provide useful information to enhance l-isoleucine or other branched-chain amino acid production in C. glutamicum.

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