Pigments and citrinin production during cultures of Monascus in liquid and solid media

As a part of the investigations on red pigment production by Monascus species, an antibacterial compound was isolated from the supernatant fungal cultures and identified as the nephrotoxic agent, citrinin. It was produced both by Monascus purpureus as well as M. ruber and was synthesized the pigments, through the polyketides pathway. As Monascus red pigments are commonly used in Asia as food additives, where these are produced on rice, the commercial preparations obtained by SSF were analyzed. These contained no citrinin at all, while our preparations obtained by submerged cultures contained a non-negligible fraction of citrinin. In the liquid medium, M. purpureus and M. ruber produced citrinin at concentrations of 240 and 370 mg/l, respectively, while in SSF on rice, the production was 100 and 300 mg/kg of dried fermented rice powder, respectively.