Optimization of the production and isolation of exopolysaccharides from Streptomyces thermophilus and strong evidence for their growth-associated biosynthesis
1997
Degeest, B. | Ven, S. van de | Vuyst, L. de (Vrije Univ., Brussel (Belgium). Faculty of Sciences. Dept. of Biotechnology)
In this study several Streptococcus thermophilus strains have been screened as to their capacity to produce exopolysaccharides. After a preliminary screening on different media on ruthenium red agar plates and on different carbon and/or energy sources, an improved, easy and valid method for direct isolation of exopolysaccharides from fermented milk enabled the isolation of four strains which displayed considerable slime formation. The influence of physical factors such as temperature, pH and oxygen tension as well as chemical factors (initial lactose concentration, carbon/nitrogen ratio) were optimized in milk medium to obtain optimal production kinetics and a high exopolysaccharide yield. Using these optimal conditions, exopolysaccharide production could also be observed in MRS broth.
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