Luo Zhiting, Guo Yuan, Liu Jidong, Qiu Hua, Zhao Mouming, Zou Wei, Li Shubo
College of Light Industry and Food Engineering, Guangxi University, Nanning, 530004 China.
National Engineering Research Center for Non-Food Biorefinery, Guangxi Academy of Sciences, Nanning, 530004 China.
Biotechnol Biofuels. 2016 Jun 29;9:134. doi: 10.1186/s13068-016-0537-7. eCollection 2016.
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.
聚γ-谷氨酸（γ-PGA）是一种天然存在的生物聚合物，由L-谷氨酸、D-谷氨酸或两者的重复单元组成。由于一些细菌能够从可再生生物质中大量生物合成γ-PGA，γ-PGA被认为是一种很有前景的生物基化学品，并且由于其可生物降解、无毒和无免疫原性的特性，已广泛应用于食品、医疗和废水处理行业。在这篇综述中，我们探讨了γ-PGA的性质、生物合成途径、生产策略及应用。特别详细介绍了γ-PGA的微生物生物合成及其生产调控的分子机制。事实证明，基因工程以及生长培养基的优化、过程控制和下游加工是降低生产成本以及控制分子量和构象/对映体性质的有效策略，这些性质有助于筛选有竞争力的γ-PGA生产者。最后，结合该领域的最新进展、挑战和趋势，讨论了微生物生产γ-PGA的未来前景。
