Isolation, characterization and optimization of Cystobasidium minutum for phytase production

Abstract

Introduction and Aim: Phytic acid (myo-inositol 1, 2, 3, 4, 5, 6-hexakis dihydrogen phosphate), a storage form of phosphorus is present in legumes, cereals and oilseeds. By forming insoluble complexes with proteins and divalent cations, it serves as an anti-nutrient in animal feed. Phytase (EC 3.1.3.8), a special class of phosphomonoesterases, catalyse the conversion of inorganic phosphate into mono-, di-, tri-, tetra-, and penta-phosphates of derivatives of myo-inositol. It is an important enzyme in food and feed industries. The present study aimed at isolation, molecular identification and optimization of physico-chemical parameters for phytase production by a red pigmented yeast Cystobasidium minutum. Materials and Methods: The phytase activity was estimated by using sodium phytate as substrate and the production of phytase under varied temperature, pH, agitation, incubation time, carbon and nitrogen sources. Results: The results showed maximum activity of 91.86 and 27.13 U/ml at 35°C and pH 5.5. At an agitation speed of 150 rpm and 120h of incubation time the enzyme activity was 18.9 and 21.4 U/ml respectively. Among the carbon sources tested sucrose served for highest enzyme activity of 26.33 U/ml and ammonium sulphate served the sole source of nitrogen and showed an activity of 50.12 U/ml. Conclusion: Cystobasidium minutum (Rhodotorula minutum) produced maximum phytase enzyme in an optimized physical and chemical condition. Hence, from the present investigation, it is found that optimization of physic-chemical conditions may be a promising tool for the growth of organisms and also maximum yield of any metabolite.