Production of Monascus Purpureus Pigments; Influenced by Amidase and Acid Protease Activity

Monascus purpureus grown on rice secretes several polyketide pigments used for coloring foods. The amidase enzymes, L-asparaginase and L-glutaminase activities were identified by rapid plate assay. The pink zone formed around colonies of M. purpureus (Microbial Type Culture Collection [MTCC] 410), hyper pigment (Central Food Research [CFR] 410-11) and albino (CFR 410-22) were 2.0, 2.4 and 1.2 cm, respectively. The L-asparaginase (0.103 IU) and L-glutaminase (0.139 IU) activity was comparatively more in CFR 410-11 than MTCC 410 and CFR 410-22. Higher acid protease activity (5,170 Units) was observed in CFR 410-22. The mutant CFR 410-11 has secreted more red pigment cultured on rice (2.248 optical density [OD] units) and in broth (0.841 OD units). Significant difference in amidase and acid protease activities of MTCC 410 and its mutant CFR 410-11 and CFR 410-22 have revealed the importance of these enzymes in pigment production. PRACTICAL APPLICATION The isolated albino (CFR 410-22) mutant has overproduced acid protease enzyme. This enzyme finds applications in debittering of protein hydrolysate, cheese ripening and preparation of amino acid mixture from protein. The amidase enzymes produced by Monascus sp. may play a major role in tumor inhibition.