The mechanism of the interaction between the formed emulsification and yeast cells in biotransformation system

Abstract

AbstractBACKGROUNDThe natural gamma‐decalactone (GDL) produced via microbial biotransformation is one of remarkable lactone compound applied in the field of foods, pharmaceuticals, and cosmetics. Whereas, emulsification generated during the biotransformation brings difficulties to the separation of GDL and reduces the efficiency of industrial production. In order to improve the yield of GDL, the mechanism of the interaction between the formed emulsification and yeast cells was investigated.RESULTSThe relationships of substrate ricinoleic acid (RA) droplet size, concentration, GDL concentration, and the productivity of yeast were investigated. During the biotransformation, a kind of biosurfactant was identified. The result showed that the structure of biosurfactant was mainly three lipopeptide analogues with cyclic structure. Most RA droplet size fluctuated from 2000 nm to the range of 400–4500 nm when GDL generation rate was higher at 24–36 h. In addition, GDL generation rate could be advanced by 12–24 h with droplet size of RA at about 3000 nm. The local high concentration of GDL solubilized in RA caused a great toxicity on cells after 36 h.CONCLUSIONThis study provides a remarkable theoretical guidance for the industrial biotransformation of GDL. Controlling the droplet size of RA and reducing the concentration of GDL when the emulsification generated are very significant. Finding a better extractant which is more soluble to GDL than RA and developing an In Situ Product Removal (ISPR) of GDL system is essential to improve the GDL productivity. © 2021 Society of Chemical Industry (SCI).