| 摘要 |
Novel, improved, water insoluble, gel-forming beta -1,3-glucan exopolysaccharide is described having an intrinsic viscosity of at least about 6.0 dL/g, as measured by the procedure described in the disclosure, and improved gel strength and molecular weight qualitites. The novel exopolysaccharide is produced in a process having two phases, a growth phase and a stationary exopolysaccharide biosynthesis phase. In the latter phase, agitation are aeration are controlled to provide mixing sufficient to produce a homogeneous medium and oxygen transfer sufficient for be aerobic biosynthesis without significantly decreasing the intrinsic viscosity of the exopolysaccharide product. Maintaining the dissolved oxygen concentration in the aqueous medium in the stationary phase at a value of at least 2.0 mg 02/L, preferably at least 6.0mg 02/L, results in increased specific rate of exopolysaccharide product production. The novel products are useful as thickening agents and the like. |
