Production of red pigments by Monascus ruber CCT 3802 using lactose as a substrate

- Hydrolyzed lactose is a good substrate for monascus pigments production.
- Monascus can use the lactose as substrate on submerged fermentation.
- A new alternative for monascus pigments production from submerged fermentation.

The use of lactose as a carbon source for the production of pigments by Monascus ruber was the aim of this study. 500-mL Erlenmeyer flasks containing 160 mL of culture medium with different substrates (glucose, lactose and hydrolyzed lactose) were incubated at 30 °C in shaker for 7 days. Production of pigment andl biomass in the three culture media was observed; however, the consumption of reducing sugars and biomass production for culture containing only lactose were inhibited, with a decline in pigment production after 72 h of cultivation. In medium containing hydrolyzed lactose, there was maximum pigment production of 7.58 AU510, exceeding culture containing glucose which presented 7.36 AU510. The average production of red pigment was higher in glucose media (0.072 AU510 h−1), followed by medium containing hydrolyzed lactose (0.059 AU510 h−1). However, the average production of yellow and orange pigments was higher for hydrolyzed lactose media (0.043 AU400 h−1 and 0.053 AU470 h−1, respectively). Pigment produced in hydrolyzed lactose media appeared lighter but redder and more yellow than in glucose media. The Hue angle values for the glucose and hydrolyzed lactose media showed that both tended to redness. These results evidenced the importance of this study for the use of lactose in the production of biopigments by M. ruber, since it is present in agro-industrial residues of great relevance, as is the case of cheese whey.