A Myo-Inositol-Inducible Expression System for and Its Application.

is one of the important industrial microorganisms for production of amino acids and other value-added compounds. Most expression vectors used in are based on inducible promoter (P or P ) 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 , multiple cloning sites, and terminator, the pMI-4 (6,643 bp) contains the cassette and the myo-inositol-inducible promoter P . The pMI-4 could stably replicate in the host. Meanwhile, the non-myo-inositol degradation host strain ΔΔΔΔ for maintaining the pMI-4 was developed. Overexpression of and using pMI-4 resulted in a significant accumulation of 5-aminolevulinic acid, indicating its potential application in metabolic engineering and industrial fermentation.