Optimization of cultivation conditions for Monascus pigments by solid fermentation of Monascus
Response surface methodology (RSM) based on a three-factor Box-Behnken design of experiments was used to optimize the Monascus pigment content and citrinin content by solid fermentation using Monascus. The critical factors selected for the investigation were temperature, time of cultivation and moisture content. The objectives of this present work were to locate optimum levels of these process parameters, and to find out interaction among them for enhancement of the yield of Monascus pigments. By solving the regression equation and also by analyzing the response surface contour plots, the optimal process conditions were determined: under conditions of moisture content 37.33%, cultivation time 13.89 d and temperature 27.62 ℃, the maximum prediction of Monascus pigments color value by Monascus IFFI05032 was 3577.37 U/g. In order to obtain the maximum yield of Monascus pigment and minimum of citrinin content at the same time, condition would be located at 38.36%, 29.03 ℃ and 12.40 d. Under this conditions, the maximum predicted of Monascus pigment color value and minimum of citrinin content were found to be 2945.32 U/g, 15.60 μg/g respectively. These predicted values were also verified by validation experiment.