Optimized Culture Conditions for Enhanced Recovery of Exopolysaccharide from Pseudolagarobasidium acaciicola :A Novel Fungus Isolated from the Fruit Body of Russula nigricans , A Wild Edible Mushroom of Odisha, India

Fungal exopolysaccharides (EPS) are becoming important due to their multifarious applications with different structural forms and easy recovery. The objective of this study was to optimize submerged culture condition of a new fungal isolate Pseudolagarobasidium acaciicola obtained from fruit body of an edible mushroom, Russula nigricans. The study analyses the optimization of different parameters for enhanced production of EPS by one factor-at-a-time (OFAT) method. The influence of incubation period, initial pH value, temperature, mode of culture (static shake), culture vessel, carbon and nitrogen sources, and enhancers was studied. OFAT method revealed pH 6 with 7 days incubation statically and in dark in 150 ml Erlenmeyer flask, chemical factors like sabouraud dextrose HiVeg broth medium, xylose, yeast extract, tryptophan, K₂HPO₄, CaCl₂ and vitamin C as good conditions and components for maximum biomass and EPS production. Optimized medium developed in this study was a combination of the individually screened nutrient component, estimated the maximum EPS (1002.3 ± 189.72 mg/l) which was later expelled to 1468.1 ± 227.86 mg/l after addition of olive oil and Tween 80 at a concentration 250 : 50 μl v/v, which was much higher, and reported first time from this fungus (it means that early when medium was formulated with different chemical components we got the optimized medium giving 1002.3 mg/l of EPS but when addition of oils was performed we got more amount, i.e. 1468.1 mg/l). EPS production in a new medium might facilitate its industrial-scale production and use as a bioactive product for the welfare of mankind.