Evaluation of nutritional requirements of medicinal fungus, Pyrofomes demidoffii under submerged fermentation

Abstract

Abstract Pyrofomes demidoffii is a medicinal wood decay fungus that exhibit antimicrobial and also antioxidant properties. The aim of this study was to evaluate the optimal nutritional requirements for growth of P. demidoffii under submerged fermentation expressed in terms of mycelial dry weight. For this study, carbon, nitrogen, macro-mineral elements and vitamins sources were evaluated under submerged cultures using one-factor-at-a-time and in orthogonal design method. In one-factor-at-a-time analysis, soluble starch, yeast extract, MgSO4.7H2O and thiamine HCL produced the highest mycelial dry weight among carbon-, nitrogen-, macro-mineral element-sources and vitamins sources, respectively. In the orthogonal design method, maximum mycelial dry weight of 4.19 ± 0.03 g/L were produced under nutrient conditions of starch, 40 g/L; yeast extract, 3 g/L; MgSO4.7H2O, 0.5 g/L and thiamine HCl, 0.01 g/L. The magnitude order of the effect of all factors (R value) was in the order of soluble starch (1.75 g/L) > yeast extract (0.99 g/L) > thiamine HCl (0.87 g/L) > MgSO4.7H2O (0.51 g/L). The optimal mycelial dry weight could be produced at concentration of 40 g soluble starch, 3 g yeast extract, 0.01 g thiamine HCl and 0.75g MgSO4.7H2O in 1 L of distilled water. In conclusion, this study identified the optimal nutrient sources for the optimal growth of P. demidoffii in one-factor-at-a-time, and the optimum concentration in the orthogonal design. This is the first report on optimal nutritional requirements of the Ethiopian strain of P. demidoffii. The results of this study provide a basis for industrial fermentation and for various biotechnological uses.