Development of a 2-pyrrolidone biosynthetic pathway in Corynebacterium glutamicum by engineering an acetyl-CoA balance route.

2-Pyrrolidone is widely used in the textile and pharmaceutical industries. Here, we established a 2-pyrrolidone biosynthesis pathway in Corynebacterium glutamicum, by expressing glutamate decarboxylase (Gad) mutant and β-alanine CoA transferase (Act) which activates spontaneous dehydration cyclization of GABA to form 2-pyrrolidone. Also, the 5' untranslated regions (UTR) strategy was used to increase the expression of protein. Furthermore, considering the importance of acetyl-CoA in the 2-pyrrolidone synthesis pathway, the acetyl-CoA synthetase (acsA) gene was introduced to convert acetate into acetyl-CoA thus achieving the recyclability of the economy. Finally, the fed-batch fermentation of the final strain in a 5 L bioreactor produced 10.5 g/L 2-pyrrolidone within 78 h, which increased by 42.5% by altering the level of gene expression. This is the first time to build the basic chemical 2-pyrrolidone from glucose in one step in C. glutamicum.