@article {47411, title = {Poly-gamma-glutamic acid biopolymer: a sleeping giant with diverse applications and unique opportunities for commercialization}, journal = {Biomass Conversion and Biorefinery}, year = {2023}, month = {APR}, type = {Review}, abstract = {

Poly-gamma-glutamic acid (gamma-PGA) is a biodegradable, non-toxic, ecofriendly, and non-immunogenic biopolymer. Its phenomenal properties have gained immense attention in the field of regenerative medicine, the food industry, wastewater treatment, and even in 3D printing bio-ink. The gamma-PGA has the potential to replace synthetic non-degradable counterparts, but the main obstacle is the high production cost and lower productivity. Extensive research has been carried out to reduce the production cost by using different waste; however, it is unable to match the commercialization needs. This review focuses on the biosynthetic mechanism of gamma-PGA, its production using the synthetic medium as well as different wastes by L-glutamic acid-dependent and independent microbial strains. Furthermore, various metabolic engineering strategies and the recovery processes for gamma-PGA and their possible applications are discussed. Finally, highlights on the challenges and unique approaches to reduce the production cost and to increase the productivity for commercialization of gamma-PGA are also summarized.

}, keywords = {Commercialization, Multi-nutritious, Poly-gamma-glutamic acid, Waste valorization}, issn = {2190-6815}, doi = {10.1007/s13399-021-01467-0, Early Access Date = APR 2021}, author = {Nair, Pranav and Navale, Govinda R. and Dharne, Mahesh S.} } @article {50007, title = {Genome mining of carbohydrate-active enzymes (CAZyme) and poly-γ-glutamic acid (γ-PGA) synthesis by Bacillus velezensis (WA11) directly from lignocellulosic biomass-based substrate}, journal = {Biocatalysis and Agricultural Biotechnology}, volume = {69}, year = {2025}, month = {NOV}, pages = {103747}, type = {Article}, abstract = {

Poly-γ-glutamic acid (γ-PGA/PGA), a non-toxic and biodegradable polymer with additional diverse properties such as higher heat resistance and water retention, is widely implicated in myriad applications, including agricultural and food processing, medical treatments, and cosmetics. The industrial bio-based production of γ-PGA is primarily hindered by the potential of microbial strains and substrate costs, which are attributed primarily to the carbon sources. The present study is a proof-of-concept study, wherein a bacterial isolate,\ Bacillus velezensis\ WA11 strain, was employed for the production of γ-PGA from sugarcane bagasse (lignocellulosic biomass) without any pretreatment or pre-processing. The CAZyme annotation identified several enzyme families involved in metabolizing complex polysaccharides, including cellulose, xylan, and lignin. We obtained 104.3\ g/L γ-PGA production with a productivity of 1.09\ g/L/h in the optimized synthetic medium containing maltose as a carbon source, 2.9-fold higher than the earlier study using maltose as a carbon source. Further, substituting maltose with untreated sugarcane bagasse resulted in 12\ g/L of γ-PGA, higher than most of the reported studies utilizing pretreated lignocellulosic biomass (LCB) lysates for producing γ-PGA. The present study demonstrates the production of γ-PGA using lignocellulosic biomass without pretreatment, providing a chemical-free, sustainable avenue for directly utilizing untreated lignocellulosic biomass (LCB) to produce expensive polymers by employing potential bacterial strains.

}, doi = {https://doi.org/10.1016/j.bcab.2025.103747}, author = {Yadav, Rakeshkumar and Awathare, Pranay and Shitut, Pushkar and Mahajan, Vaishnavi and Nair, Pranav and Dharne, Mahesh} }