Quantitative profiling of yeast extract and peptone components associated with sophorolipid production in Starmerella bombicola.

Sophorolipids (SLs) are microbial glycolipid biosurfactants with potential applications in the pharmaceutical, cosmetic, petroleum, and food industries. Yeast extracts (YEs) and peptones (PPs) are commonly used nitrogen sources for SL production, but their brand- and process-dependent compositions can affect productivity. Here, six YEs (YE1 to YE6) and six PPs (PP1 to PP6) were profiled by GC-MS, LC-MS, ion chromatography, ICP-MS, and post-column detection HPLC, and their effects on SL production by Starmerella bombicola NBRC 10243 were examined. Forty-nine of 103 target components were quantified. SL titers varied from 9.6 g/L with YE6 to 36.3 g/L with PP1. Partial least squares regression predicted SL production with high accuracy (R2 = 0.96, Q2 = 0.90) and suggested amino acids, cytosine, pantothenic acid, and nitrate as candidate contributors. Supplementation experiments showed that lysine, serine, methionine, ornithine, and cytosine improved SL production, especially in combination.