Isolation of Scleroglucan-Producing Fungus, Sclerotium rolfsii MT-6, from Fermented Squash and the Optimization of Submerged Culture Conditions for Scleroglucan Production

The present study mainly focused on investigating the usability of fermented squashs (Cucurbita pepo) for the isolation of new Sclerotium rolfsii strains, which is capable of producing scleroglucan in submerged culture. Among 20 Sclerotium rolfsii strains isolated, MT-6 was found to be the best strain for both scleroglucan production and mycelial biomass production. Optimal parameters for scleroglucan production by Sclerotium rolfsii MT-6 were initial pH of 5, shaking speed of 150 rpm, temperature of 28,T, cultivation time of 72 h, sucrose as a carbon source and sodium nitrate and peptone as nitrogen source. Under the optimized submerged culture conditions, maximum productions of scleroglucan and mycelial biomass in shake-flask culture were determined as 15.21 and 17.96 g/L, respectively. The present study showed for the first time that a local isolate of Sclerotium rolfsii fungus could produce scleroglucan.