文摘
Monacolin K (MK) acts as a natural inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase. Red fermented rice by Monascus spp. which is rich in MK can be used as dietary supplement to reduce the serum triglyceride and total cholesterol. A Monascus pilosus MS-1 with high-producing MK but free of citrinin had been screened in our previous investigation. Here, its solid-state fermentation parameters were optimized using statistical methods to maximize MK yield when non-glutinous rice and soybean flours were used as substrate. Maximum MK yield (17.662?mg/g) was predicted when 55?g dry substrate (20 sieve mesh), including 60?% non-glutinous rice flour and 40?% soybean flour, was put into a 250-mL conical flask, and the contents of water, acetic acid and MgSO4·7H2O were adjusted to 35?%, 0.6?% (v/w) and 0.004?mol/kg, respectively. Then, the substrate was mixed and sterilized, and scattered before cooling. Later, 13?% (v/w) inoculum pre-cultured for 36?h at 30?°C was used, then incubated at 30?°C for 60?h and followed by a further incubation at 24?°C up to 14?days. The verified MK yield was 18.733?mg/g, which was 106.06?% to the predicted MK yield. The MK yield was enhanced to 33 times after optimization. No citrinin was detected in Monascus pilosus MS-1 fermented products. These results indicate that citrinin-free MK can be produced under the optimized conditions.