Isolation of a Curdlan-Producing Bacterium and Optimization of Fermentation Medium

Abstract:

A Rhizobium sp. capable of producing curdlan was isolated from soil. The polysaccharide product was identified to be curdlan by testing the thermal property，molecule composition，infrared spectrum and molecule weight. Furthermore，the orthogonal optimization experiment was conducted to optimize the curdlan fermentation medium，and the best medium composition was 50 g/L glucose，2 g/L（NH4）2HPO4，1.5 g/L KH2PO4，1.25 g/L MgSO4，0.05 g/L FeSO4·7H2O，0.02 g/L MnSO4，0.01 g/L CoCl2·6H2O，0.01 g/L ZnCl2. Consequently，the curdlan production and glucose conversion rate were enhanced by 29.2% and 5.4% compared with those before optimization.