Abstract:Red light was used to illuminate Monascus purpureus M9 to evaluate its effects on growth, pigments, and citrinin production. The contents of citrinin and six intracellular pigments, rubropunctamine (RUM), monascorubramine (MOM), monascin (MS), ankaflavin (AK), rubropunctatin (RUN), and monascorubrin (MON), from Monascus purpureus M9 were measured using high-performance liquid chromatography (HPLC). The results indicated that continuous illumination with red light promoted mycelial growth, the synthesis and accumulation of pigments, and spore formation in Monascus purpureus M9, especially the production of cleistothecia. Furthermore, five illumination conditions stimulated the production of RUM, MOM, MS, and AK, but inhibited the yields of RUN, MON, and citrinin. Under the optimal red light illumination condition (light intensity: 300 lux, illumination time: 30 min/d, and lighting regime: 12 h), the yields of RUM, MOM, MS, and AK were increased by 53.8%, 75.2%, 42.2%, and 59.4%, respectively, and those of RUN, MON, and citrinin were decreased by 42.6%, 54.5%, and 42.5%, respectively.
