Cysteine synthase A overexpression in Corynebacterium glutamicum enhances l‐isoleucine production

Abstract

Cysteine synthase A (CysK) catalyzes the last reaction of L-cysteine synthesis in bacteria, but its moonlighting functions have been revealed recently. In this study, CysK was overexpressed in Corynebacterium glutamicum IWJ001, an L-isoleucine producer. Compared with the control IWJ001/pDXW-8, IWJ001/pDXW-8-cysK cells grew fast during log phase, and produced 26.5% more L-isoleucine in flask fermentation and 23.5% more L-isoleucine in fed-batch fermentation. The key genes aspC, lysC, hom, thrB, ilvA, and ilvBN involved in L-isoleucine biosynthesis were all upregulated in IWJ001/pDXW-8-cysK, compared with IWJ001/pDXW-8. In addition, IWJ001/pDXW-8-cysK cells were longer and thicker than IWJ001/pDXW-8 cells. Compared with IWJ001/pDXW-8, the membrane permeability increased 15.8% and biofilm formation ability decreased 71.3% for IWJ001/pDXW-8-cysK cells. The results demonstrate that CysK overexpression in C. glutamicum is a good approach to enhance L-isoleucine production.

Effect of sodium dodecyl sulfate on the production of L-isoleucine by the fermentation of Corynebacterium glutamicum

“…The activities of threonine dehydratase and acetylhydroxy acid synthase were the strongest at 26 h, but SDS had the least positive effect on the enzyme activity. In addition, there was no activity of threonine dehydratase and acetylhydroxy acid synthetase in the cells at 2 h. At this time, the addition of SDS had no effect on the production of L-isoleucine, but SDS had an inhibitory effect on the production of strain [ 28 ]. At the same time, it was found that after adding SDS at 34 h, the activities of both enzymes decreased, which had a negative effect on the production of L-isoleucine.…”

Recent Advances in Metabolic Engineering for the Biosynthesis of Phosphoenol Pyruvate–Oxaloacetate–Pyruvate-Derived Amino Acids

“…In addition, cysteine synthase A was overexpressed in an L-Ile producer C. glutamicum IWJ001 to upregulate the genes aspC , lysC , hom , thrB , ilvA , and ilvBN involved in L-Ile biosynthesis. The recombinant strain increased L-Ile yield by 23.5% at a titer of 25.33 g/L, with productivity of 0.352 g/L per hour [ 212 ].…”