Modeling Red Monascus Pigment Production on Date Waste Substrate Using Submerged Cultivation

Monascus is one of the fungi that can be used to produce red pigments with food grades. In this study, Monascus purpureus ATCC 16362 was used to produce red pigments in date waste substrates, using submerged fermentation. Response surface methodology was used to optimize three significant factors of date waste sugar concentration (20–60 g.l^-1), NaCl (6–12 g.l^-1) and initial pH (6–9). The, effects of independent variables on red pigment and biomass content were assessed. Concentrations of 20 g.l^-1 date waste sugar and 6 g.l-1 NaCl and pH 9 resulted in the maximum yield of red pigments of 6.05±0.04 AU.ml^-1 and biomass of 7.2 g.l^-1. Furthermore, substrate conversion, yield of red Monascus pigments on biomass and the volumetric productivity included 82%, 10.42 AU pigment g^-1 biomass and 5.36 g.l^-1.day-1, respectively. Therefore, from the results of this study, date waste can be used as a low-cost substrate for the production of red pigments in large-scale studies.