Effect of substrates on the production of Monascus biopigments by solid-state fermentation and pigment extraction using different solvents

Abstract

The aim of the present work was to study the potential of natural substrates for biopigment production using a strain of Monascus sp, and to compare different solvents for extracting these pigments. Rice was the best substrate for cultivation of the culture in SSF. However, some of the other substrates used also presented good biopigment production, especially corn, wheat and cassava. Cassava bagasse gave a low pigment yield, but it is an agro-industrial residue whose low price might compensate for its low yield. However, efficient pigment production with this substrate requires supplementation of the culture medium with nutrients. Optimum fermentation time for SSF in cassava bagasse was 10-11 d. The production of yellow pigments was superior to that of red pigments, but the ratio red/yellow (ABS 500/ABS 400) grew during the course of the process. The comparison of several solvents for extraction showed that methanol was the best solvent, closely followed by DMSO and ethanol. The results also indicated that a mixture of ethanol-water with ca.60% ethanol (w/w) was more efficient than other ethanol concentrations. The solvent to substrate ratio had little influence in the extraction. Finally, temperature in the range of 0°C to 60°C showed no difference in the extraction of the biopigments under static condition.