Rational high-throughput system for screening of high sophorolipids-producing strains of Candida bombicola.

A rational high-throughput screening can significantly improve the efficiency of strain screening with high performance. In this study, based on the addition reaction of unsaturated fatty acids in the sophorolipids (SLs) and I molecules, a simple and rapid high-throughput detection method for SLs was established which demonstrated a correlation coefficient (R) of 0.9106 with high-performance liquid chromatography (HPLC) method. Moreover, chlorpromazine, as a rational selecting pressure for enrichment of mutants with high cytochrome P450 enzyme activity, which was a key enzyme in the synthesis of SLs, was introduced into the high-throughput screening model. Consequently, with the aid of this effective screening system, a high-yielding mutant designated as Candida bombicola F6.5 was successfully screened out from 1500 single colonies, which presented improvements of 40.3% and 11.4% on SLs titer and yield, respectively, compared to the parent strain in a 1 L bioreactor.