Solid-state fermentation of germinated black bean (Rhynchosia nulubilis) using Lactobacillus pentosus SC65 and its immunostimulatory effect

Germinated black bean (Rhynchosia nulubilis) (GRN) has several beneficial health effects, including immunostimulation. To enhance the immunostimulatory effect of GRN, it was fermented with lactic acid bacteria (LAB). A total of 57 strains of LAB that showed good growth on GRN were isolated from various fermented foods and vegetables. Among them, Lactobacillus pentosus SC65 was selected as a starter culture for GRN fermentation. Optimum solid-state fermentation conditions of GRN with L. pentosus SC65 (GRN-SC65) were: water content of 40% (v/w), fermentation time of 24 h, fermentation temperature of 30 °C, and inoculation volume of 5% (v/w). RAW264.7 cells treated with hot water extract of GRN-SC65 showed high nitric oxide production and phagocytic activity, indicating high immunostimulatory activity of GRN-SC65.