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 I2 molecules, a simple and rapid high-throughput detection method for SLs was established which demonstrated a correlation coefficient (R2 ) 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.