Influence of the nitrogen source on the production and rheological properties of scleroglucan produced by Sclerotium rolfsii ATCC 201126

Scleroglucan production by Sclerotium rolfsii ATCC 201126 has been studied using nitrate or ammonium as nitrogen sources at several concentrations. In all the experiments carried out, both growth and production were modelled by an unstructured kinetic model using logistic and Luedeking-Piret equatio ns for describing growth and production, respectively. The kinetic paramete rs for growth (mu and Y-XN) and for production (alpha and beta) were obtain ed by fitting the data to the model using the single-response non-linear re gression technique by means of the algorithm of Marquardt coupled to a four th-order Runge-Kutta algorithm. Biomass and scleroglucan production were hi gher when nitrate was the nitrogen source. Rheological properties of sclero glucan produced using nitrate as nitrogen source were studied and rheologic al parameters calculated, revealing similarity between this biopolymer and commercial scleroglucan.