Process optimization in ginseng fermentation by Monascus ruber and study on bile acid-binding ability of fermentation products in vitro

Ginseng (Panax ginseng C. A. Meyer) is a famous Traditional Chinese Medicine, which is widely used to treat cardiovascular disease. Monascus ruber (M. ruber) is a fungus used in food and medicine fermentation, and lovastatin, its metabolite, is used extensively in the treatment of dyslipidemia. In this study, ginseng has been fermented by M. ruber, and the response surface methodology (RSM) was applied to optimize fermentation parameters to obtain optimal fermentation system, with further exploring to lipid-lowering activity of P. ginseng C. A. Meyer-M. ruber fermentation products (PM). The concentration of ginseng, temperature, and rotating speed were set as variables and the lovastatin yield was optimized by a Box-Behnken design (BBD) analyzed by RSM. The binding capacity of PM for sodium taurocholate and sodium cholate was assayed by UV spectrophotometry. The highest content of lovastatin production (85.53 μg g^-1) was obtained at a ginseng concentration of 1.96%, temperature of 30.11 °C, and a rotating speed of 160.47 rpm. PM exhibited bile acid binding capacity, which was stronger than unfermented ginseng. The RSM can be used to optimize the fermentation system to obtain the best fermentation process. In addition, the fermentation of ginseng by M. ruber can enhance the lipid-lowering effect.