Isolation and Identification of Lactobacillus plantarum and Its Effect on Pigment Production by Monascus

A lactic acid bacteria (LAB) strain BD-1 was isolated from red fermented bean curd, and the effect of BD-1 and its fermentation supernatant on the production of Monascus pigments (MPs) by Monascus purpureus ATCC 16365 was studied. The results showed that BD-1 was identified as Lactobacillus plantarum through Gram staining, physiological and biochemical profiles and 16S rRNA gene sequencing. Five different inoculum sizes of 0.2%, 0.4%, 0.6%, 0.8% and 1.0% were tested for strain BD-1 and ATCC 16365 was cultured for 0, 24 or 48 h. It was found that adding 0.6% BD-1 to the fermented medium with ATCC 16365 after culture for 24 h markedly increased the color value and synthesis of extracellular Monascus pigments (EMPs) and intracellular Monascus pigments (IMPs). Under this condition, the color values of EMPs and IMPs were (6.24 ± 0.05) and (288.14 ± 6.82) U/mL, and their synthesis was increased by (146.55 ± 7.84)% and (16.07 ± 0.30)% compared with the control group, respectively. In addition, adding the fermentation supernatant of BD-1 to ATCC 16365 also remarkably increased the color value and synthesis of EMPs, which were increased to 4.20 U/mL and by (29.85 ± 5.40) % compared to the control group, respectively. In summary, the optimal inoculum size of BD-1 for MPs production was 0.6%.