Production of metabolites from mutant strains of Rhodotorula minuta upon varied temperature

Abstract

The present investigation focussed on the production of metabolites such as phytase, carotenoid pigment, lipids, and exopolysaccharide content by a hyper producing putative mutant strain of Rhodotorula minuta. Several putative mutants namely MR5, MR7, MR9, MR13, CMR1, and CMR2 were isolated after a series of UV and chemical (Ethyl methane sulfonate, EMS) mutagenesis of an orange yeast strain, Rhodotorula minuta. The effect of different temperatures on the production of metabolites by these mutants was tested. The result showed an highest phytase from CMR1 (26.735 U/ml) and MR7 (21.620 U/ml) at 30 and 35°C respectively. With respect to exopolysaccharide production, highest yield of 1000 and 1300 mg/l was obtained at 40°C with MR9 and CMR2, respectively, while lipid production from MR5 (34 g/kg) and CMR1 (11 g/kg) was at 25°C. Total carotenoid content in MR13 was 445 µg/kg at 35°C and in CMR1 it was found to be 454 µg/kg dry cell weight at 25°C. All the putative mutant strains of Rhodotorula minuta produced highest amount of one or the other tested metabolites. The CMR1 strain produced highest amount of both carotenoid and phytase, CMR2 strain produced good amount of exopolysaccharide while MR5 strain showed maximum accumulation of lipid content in the cells.