Fermentative production of microbial exopolysaccharides

This chapter describes the production processes for various microbial polysaccharides, starting from substrates to fermentation and downstream processing, with a special focus on bioreactor design and process variants. The main scope is on the differences between fungal and bacterial polysaccharide production based on hyphal growth and cell division, which massively influences, for example, bioreactor geometry and design as well as mixing properties. The main aspects, such as handling of the viscous fermentation broth and oxygen supply, are described and discussed. In addition, several stirrer designs for microbial polysaccharide production are presented and solutions for minimizing the viscosity within the production process, such as water in oil emulsions, are discussed. The chapter thus serves as a review of the development on polysaccharide production within the last decades.