Cheese whey as a potential substrate for Monascus pigments production

The present study had the objective of producing pigments by Monascus ruber in solid medium, using the cheese whey as substrate. Different cheese whey concentrations (0, 5, 10, 20, 40 and 80 g L-1) and pH values (2.0, 3.0, 4.0, 5.0, 6.0, 7.0 and 8.0) were tested. There was growth of the microorganism for all concentrations of cheese whey applied and there was a significant difference between the radial growth rates of the fungus obtained for each medium when compared to the control. When analyzed under different pH values, M. ruber growth rates were higher at pH 6.0 in culture medium containing 20 g L-1 of whey powder. At extreme pH values, such as pH 2.0 and 8.0, the growth of the fungus presented inhibition and the visual aspect differed, presenting yellow and red coloration, respectively. The growth rate at pH 3.0, 4.0 and 5.0 did not differ significantly (p > 0.05), however, it was observed that in different pH values, orange and red pigments were produced. These results demonstrate the potential of cheese whey as a substrate for Monascus growth and, consequently, the production of pigments.