Alkaliphilic lysine decarboxylases for effective synthesis of cadaverine from L-lysine

The enzymatic decarboxylation of L-lysine using lysine decarboxylase is a promising biological approach for producing cadaverine, a versatile platform chemical for bio-polyamides. However, due to the problem with elevated pH in the reaction solution during the enzymatic process, it is desirable to use lysine decarboxylases effectively active in alkaline conditions. In this study, the catalytic properties of three lysine decarboxylases from Selenomonas ruminantium (srLDC), Vibrio vulnificus (vvLDC), and Geobacillus thermodenitrificans (gtLDC) were characterized, and the applicability of the enzymes in alkaline conditions was investigated. Among the three enzymes, only vvLDC exhibited effective activity in alkaline pH conditions. The conversion rate of vvLDC was 1.5-fold higher than that of srLDC and 5.3-fold higher than that of gtLDC in pH 9.0. The results indicate that vvLDC is more advantageous than srLDC and gtLDC for the enzymatic conversion of L-lysine to cadaverine in alkaline conditions.