Frontiers in Bioengineering and Biotechnology (Nov 2021)

A Myo-Inositol-Inducible Expression System for Corynebacterium glutamicum and Its Application

  • Nan Lu,
  • Chenglin Zhang,
  • Wenjie Zhang,
  • Haoran Xu,
  • Yuhong Li,
  • Minhua Wei,
  • Jing Meng,
  • Yan Meng,
  • Junzhe Wang,
  • Ning Chen

DOI
https://doi.org/10.3389/fbioe.2021.746322
Journal volume & issue
Vol. 9

Abstract

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Corynebacterium glutamicum is one of the important industrial microorganisms for production of amino acids and other value-added compounds. Most expression vectors used in C. glutamicum are based on inducible promoter (Ptac or Ptrc) activated by isopropyl-β-D-thiogalactopyranoside (IPTG). However, these vectors seem unsuitable for large-scale industrial production due to the high cost and toxicity of IPTG. Myo-inositol is an ideal inducer because of its non-toxicity and lower price. In this study, a myo-inositol-inducible expression vector pMI-4, derived from the expression vector pXMJ19, was constructed. Besides the original chloramphenicol resistance gene cat, multiple cloning sites, and rrnB terminator, the pMI-4 (6,643 bp) contains the iolRq cassette and the myo-inositol-inducible promoter PiolT1. The pMI-4 could stably replicate in the C. glutamicum host. Meanwhile, the non-myo-inositol degradation host strain C. glutamicumΔiolGΔoxiCΔoxiDΔoxiE for maintaining the pMI-4 was developed. Overexpression of hemAM and hemL using pMI-4 resulted in a significant accumulation of 5-aminolevulinic acid, indicating its potential application in metabolic engineering and industrial fermentation.

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