Production of lndole-3-acetate in Corynebacterium glutamicum by Heterologous Expression of the lndole-3-pyruvate Pathway Genes

摘要

Biosynthesis of indole-3-acetate (IAA) from L-tryptophan via indole-3-pyruvate pathway requires three enzymes including aminotransferase, indole-3-pyruvate decarboxylase, and indole-3-acetate dehydrogenase. To establish a bio-based production of IAA,the aspC, ipdC, and iadl from Escherichia coli, Entero-bacter cloacae, and Ustilago maydis, respectively, were expressed under control of the tac, ilvC, and sod promoters in C. glutamicum. Cells harboring ipdC produced tryptophol, indicating that the ipdC product is functional in this host. Analyses of SDS-PAGE and enzyme activity revealed that genes encoding AspC and Iadl were efficiently expressed from the sod promoter, and their enzyme activities were 5.8 and 168.5 nmol/ min/mg-protein, respectively.The final resulting strain expressing aspC, ipdC, and iadl produced 2.3 g/1 and 7.3 g/1 of IAA from 10 g/1 L-tryptophan, respectively, in flask cultures and a 5-L bioreactor.