title: Microbial synthesis of poly-γ-glutamic acid: current progress, challenges, and future perspectives.
abstract: Poly-γ-glutamic acid (γ-PGA) is a naturally occurring biopolymer made from repeating units of l-glutamic acid, d-glutamic acid, or both. Since some bacteria are capable of vigorous γ-PGA biosynthesis from renewable biomass, γ-PGA is considered a promising bio-based chemical and is already widely used in the food, medical, and wastewater industries due to its biodegradable, non-toxic, and non-immunogenic properties. In this review, we consider the properties, biosynthetic pathway, production strategies, and applications of γ-PGA. Microbial biosynthesis of γ-PGA and the molecular mechanisms regulating production are covered in particular detail. Genetic engineering and optimization of the growth medium, process control, and downstream processing have proved to be effective strategies for lowering the cost of production, as well as manipulating the molecular mass and conformational/enantiomeric properties that facilitate screening of competitive γ-PGA producers. Finally, future prospects of microbial γ-PGA production are discussed in light of recent progress, challenges, and trends in this field.
authors.affiliation: College of Light Industry and Food Engineering, Guangxi University, Nanning, 530004 China.
authors.forename: Zhiting
authors.initials: Z
authors.lastname: Luo
authors.affiliation: National Engineering Research Center for Non-Food Biorefinery, Guangxi Academy of Sciences, Nanning, 530004 China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Guo
authors.affiliation: College of Light Industry and Food Engineering, Guangxi University, Nanning, 530004 China.
authors.forename: Jidong
authors.initials: J
authors.lastname: Liu
authors.affiliation: College of Light Industry and Food Engineering, Guangxi University, Nanning, 530004 China.
authors.forename: Hua
authors.initials: H
authors.lastname: Qiu
authors.affiliation: College of Light Industry and Food Engineering, Guangxi University, Nanning, 530004 China.
authors.forename: Mouming
authors.initials: M
authors.lastname: Zhao
authors.affiliation: College of Bioengineering, Sichuan University of Science and Engineering, Zigong, 643000 Sichuan China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zou
authors.affiliation: College of Light Industry and Food Engineering, Guangxi University, Nanning, 530004 China.
authors.forename: Shubo
authors.identifier: 0000-0002-7656-6719
authors.initials: S
authors.lastname: Li
keywords: Industrial applications; Metabolic regulation; Microbial fermentation; Poly-γ-glutamic acid; Process optimization; Strain development