Investigating the Effect of Sodium Azide and Nitrous Acid on the Morphological Characteristics of Monascus Purpureus and Pigment Production

Monascus purpureus is a filamentous ascomycetes fungus that has the ability to produce natural pigments. The aim of the present study was to investigate the effects of mutagenic chemical agents of Sodium Azide and Nitro Acid on the morphology of Monascus purpureus and stable pigment production by this fungus.

Initial sporulation of Monascus purpuoreus was affected by chemical mutagens (Sodium Azide and Nitrous Acid). Then, the morphological features (appearance and microscopy) of the suspected colonies were examined. Wild and selected colonies were cultured under the submerge fermentation for up to two generations to measure biomass and pigment under immersion conditions.

The production of biomass and yellow, orange, and red pigments in the first and second generation of NA2 (nitrous acid, 0.4 M, 45 min), NA3 (nitrous acid, 0.4 M, 30 min), and NA6 (nitrous acid, 0.2 M, 30 min) samples did not change significantly (P <0.05). NA2 sample significantly produced the maximum amount of pigment (P <0.05). The concentrations of yellow, orange, and red pigments produced by this sample were 0.64, 0.42, and 0.45 units per milliliter, respectively.

In the present study, the morphology of all selected samples showed changes compared to the wild sample. Most of the selected samples produced significantly more pigments than the wild strain which were stable for up to two generations (P <0.05). The treatment method of Monascos purpureus with nitrous acid can successfully lead to the production of samples with higher and more stable pigment production.