Abstract:  With carbon, nitrogen, pH value and fermentation liquid volume in flask as test factors, producing conditions of pigment by Monascus rubber were optimized by L9(34) orthogonal test. Signal test results showed that corn powder, maltose and starch are the better carbons; NaNO3, soya powder, NH4Cl are the better nitrogen; pH3.8, pH5.4, pH7.0 are the better pH values of substrate; and 100 ml/250 ml, 125 ml/250 ml, 150 ml/250 ml are the better fermentation liquid volumes. Orthogonal test results showed that A3B1C1D3 is the optimum conditions combination for producing Monascus rubber pigments, that is to say, maltose as carbon, soya powder as nitrogen, pH3.8 and 150 ml/250 ml fermentation liquid volume in flask are the optimum conditions.

Key words: liquid fermentation, Monascus rubber, monascus pigment