Comparative study of Monascus sanguineus and Monascus purpureus for red pigment production under stress condition

Monascus sp. is known for pigment production. Monascus sp. synthesized pigment has been used as food colorants for quite a long time. According to literature, many strains have been isolated from Monascus, which are internationally acknowledged and there are many studies on Monascus purpureus, Monascus anka or other species. In the present study, Monascus strain was isolated and identified as Monascus sanguineus on the molecular basis. This strain was then compared with a reference strain Monascus purpureus MTCC 410 for red pigment production under stress condition. Both strains were treated with different stress conditions viz. different concentration of glycerol, NaCl, peptone and also with the spores treated at different temperatures. Both strains had shown increased pigmentation under stressed condition. Maximum pigment yield was observed with 0.5M glycerol concentration for both strains (Monascus sanguineus 33.4 color value units (CVU)/ml, Monascus purpureus 36.7 CVU/ml). For salt stress, both strains produced maximum pigment with 3% NaCl concentration. At 12% NaCl concentration, both the strains showed very slow growth and almost no pigment yield. When spores were treated with different temperatures, Monascus sanguineus produced maximum pigment with spores treated at 90°C, whereas Monascus purpureus lost viability at this range.