Production of new types of sophorolipids by Candida batistae

Sophorolipids (SLs) are glycolipid biosurfactants abundantly produced from different feedstocks by yeasts, and have been widely developed for various applications. In this study, we searched for novel SLs, aiming to broaden the functions and application range. As a result of screening based on the phylogenetic information of a known SL producer, we found that Candida batistae CBS 8550 produces new types of SLs. Interestingly, the present product mainly constituted acid-form SLs (more than 60% of the total SLs), considerably different from conventional SLs that mainly constitute lactone-form ones. In the shake-flask culture with glucose and olive oil as the carbon sources, the yeast produced 6 g/L of SLs after 3 days cultivation. The critical micelle concentrations of the present SL product and isolated acid-form SL (GL-A) were 366 and 138 mg/L, respectively, while those of conventional SLs and isolated acid-form SL were 17 and 95 mg/L, respectively. From these results, the phylogenetic approach should lead to the discovery of new biosurfactant producers, and the yeast product possessing high hydrophilicity may facilitate a broad range of applications for SLs.