Influences of fermentation parameters on lovastatin production by Monascus purpureus using Saccharina japonica as solid fermented substrate

Abstract

In this study, Saccharina japonica (brown seaweed) was fermented in solid state by Monascus purpureus to maximize lovastatin production, the response surface methodology (RSM) was applied to optimize four different fermentation parameters: temperature (25−35 °C), time (10−20 days), glucose (0.1–1.5%) and peptone (0.1–0.7%) concentration. The predicted combination of process parameters yielding the highest rate of lovastatin production (13.40 mg gdfs−1) was obtained at a temperature of 25.64 °C, a fermentation time of 14.49 days, glucose concentration of 1.32% and peptone concentration of 0.20%, with 92.85% validity. Among the studied factors, glucose, incubation time and temperature most strongly influenced lovastatin production. Triplicate experiments in which lovastatin was produced under optimal conditions resulted in a mean yield of 13.98 mg gdfs−1 with 207.84 mg gdfs−1 biomass. Liquid chromatography–tandem mass spectrometry (quadrupole time-of-flight) analysis confirmed the ionic molecular weight of lovastatin (405.26). Lovastatin from the M. purpureus fermented S. japonica exhibited thermal stability, superoxide dismutase activity and a cholesterol esterase inhibition activity that was higher than that of unfermented sample and showed no toxic effect on Caco-2 cell. Thus, S. japonica was a suitable substrate to maximize lovastatin production from M. purpureus at optimum condition for applying in food and pharmaceutical industry.