Chapter 22 - Bioconversion of Whey Lactose into Microbial Exopolysaccharides

Abstract

This chapter reviews the bioconversion of whey lactose into microbial exopolysaccharides (EPS). It also emphasizes challenges facing the fermentation process as well as the criteria to be considered to develop it into an effective and valuable bioconversion process. Microbial EPS such as xanthan gum and alginate continue to receive increasing applications in response to the demands for desirable product texture and enhanced processibility of nutritional and healthful food products. These polymers require simple sugars as building blocks and are produced via natural fermentation processes using specific microorganisms. The inherent specificity of the enzymes involved and the controllability of a bioprocess make bioconversion into EPS an ideal candidate for the effective utilization of whey lactose. Bioconversion is considered the most feasible means to effectively transform milk lactose from a low-value feedstock into value-added products. However, the direct fermentation of lactose by participating microorganisms usually suffers from a limited conversion rate as is found in yeast fermentation. The utilization of lactose as the building blocks for the synthesis of microbial EPS thus appears to be a favorable option. Microbial EPS already have many important applications in food, chemical, and pharmaceutical industries, and they continue to find new uses in emerging markets.