Recent Advances in Poly-(γ-Glutamic Acid) Production by Microbial Fermentation

Poly (γ-glutamic acid) (γ-PGA) is a microbial biopolymer composed of D- and L-glutamic acid monomers connected by γ-amide linkage. γ-PGA is considered a promising biopolymer and has broad applications in food, medicine, agriculture, daily chemicals, and environmental protection due to its water-soluble, biodegradable, and nontoxic properties. The production of γ-PGA has already been established on an industrial scale. This chapter provides updated information about strain breeding, biosynthesis, fermentation, purification, and application of γ-PGA. The biosynthetic mechanism of γ-PGA and regulation of molecular weight by synthetic biology are covered in detail. The current and potential applications of γ-PGA have also been reviewed. Finally, future outlooks of microbial γ-PGA production and application are discussed in recent progress, challenges, and trends in this field. This chapter contributes to the further understanding of efficient production of diversified γ-PGA and will serve as valuable references for reducing the cost of production and further development of commercial-scale applications of γ-PGA.