| Curdlan is a water-insoluble microbial exopolysaccharide. It has drawn considerable interest in food application because of its unique rheological and thermal gelling properties. In addition, it was also widely used and researched in pharmaceutical and other industrial application. This paper describes the selection of high producing strain?the optimization of fermentation process and studies of its fermentation kinetics, method for investigating the curdlan concentration with Congo red was established.Through the treatment on the curdlan-yield strain with UV and 8-mop, a mutant strain Agrobacterium radiobacter G-1 which has higher curdlan productivity was selected from the high sugar and indicating plate. The optimum medium was obtained through single factor test and orthogonal test. The curdlan product amounts to 47.2g/L, with initial source concentration 7%?pH 7.0, shaking in 32℃ at 200rpm for 96h, and the optimal seed volume is 8%. The shaking flask fermentation indicates a leading level in our country in each item of economic and technological specifications. The kinetics for curdlan fermentation was studied and the mathematical kinetic models which provided a reasonable description for biomass, product and substrate variation along with the fermentation process were established.The conditions for the quick investigation of curdlan concentration in the fermentation was obtained through the analysis of the colorimetric reaction with Congo red. It is a simple, effective and sensitive method and provide a method for the analysis of curdlan concentration on line during the industrial production. The structure and components of purified curdlan are analyzed by IR, 13C NMR and paper chromatography suggest that the purified curdlan contained exclusively linear P-(l-3)-D glucan; Meanwhile, we found that the curdlan of the strain A.R.G-1 has an excellent characterization of rheology and gelling properties.
|
PDF Full Text Request