Improvement of monacolin K/citrinin production ratio in Monascus purpureus using UV mutagenesis

Monascus purpureus MTCC 1090 is a fungus that produces monacolin K, gamma-aminobutyric acid (GABA) and citrinin under solid-state and submerged fermentation. The production of citrinin has a negative impact on its acceptance as a nutraceutical due to its neurotoxic, hepatotoxic and genotoxic effects. The purpose of the present study is to produce a M. purpureus mutant with zero concentration of citrinin production by random mutagenesis using ultra-violet (UV) irradiation. Mutants were screened on the basis of changes in their cultural characteristics and ratio of inhibition against Bacillus subtilis by the cross-streak method. Mutant M. purpureus 254 produced no citrinin as analysed by high-performance liquid chromatography and showed an increase in monacolin K production of about 74.32% in an optimised fermentation medium.