Bio‐Based Production of Dimethyl Itaconate From Rice Wine Waste‐Derived Itaconic Acid

Dimethyl itaconate is an important raw material for copolymerization, but it is not synthesized from itaconic acid by organisms. Moreover, Corynebacterium glutamicum is used as an important industrial host for the production of organic acids, but it does not metabolize itaconic acid. Therefore, the biosynthetic route toward dimethyl itaconate from itaconic acid is highly needed. In this study, a biological procedure for dimethyl itaconate production is developed from rice wine waste-derived itaconic acid using the engineered C. glutamicum strain. The first step is to investigate the effect of the co-overexpression of the codon-optimized cis-aconitic acid decarboxylase (CadA*) and a transcriptional regulator of genes involved in acetic acid metabolism (RamA) on itaconic acid production. The second step is to convert itaconic acid into dimethyl itaconate by lipase-catalyzed esterification. The CadA* and RamA-overexpressing CG4 strain increases the itaconic acid concentration under N-starvation with glucose and acetic acid compared with the concentration produced in the base mCGXII medium with glucose. Furthermore, the rice wine waste-derived itaconic acid is successfully converted into dimethyl itaconate using lipase from Rhizomucor miehei and a methanol substrate. This study is the first trial for bio-based production of dimethyl itaconate from rice wine waste-derived itaconic acid.