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.