# Purification, Structural Characterization, and Antibacterial Evaluation of Poly-γ-Glutamic Acid from Bacillus subtilis

**Authors:** Gobinath Chandrakasan, Genaro Martin Soto-Zarazúa, Manuel Toledano-Ayala, Priscila Sarai Flores-Aguilar, Said Arturo Rodríguez-Romero

PMC · DOI: 10.3390/polym18020172 · Polymers · 2026-01-08

## TL;DR

This paper explores the production and characterization of poly-γ-glutamic acid from Bacillus subtilis, highlighting its antibacterial properties and potential biomedical uses.

## Contribution

The study introduces a novel biological source of γ-PGA from Bacillus subtilis and evaluates its antibacterial potential.

## Key findings

- γ-PGA was successfully produced using shake flask fermentation with different growth media.
- FT-IR, HPLC, and GC-MS confirmed the presence of key functional groups and purity of γ-PGA.
- The study provides insights into optimizing γ-PGA production for antibacterial applications.

## Abstract

Extracellular poly-γ-glutamic acid (γ-PGA) produced by Bacillus species demonstrates significant antibacterial properties, positioning it as a promising candidate for diverse biomedical and industrial applications. This study focused on molecular identification of Bacillus subtilis using Polymerase Chain Reaction (PCR) and evaluated the initial production of γ-PGA from a novel biological source of Bacillus subtilis. Shake flask fermentation was utilized for γ-PGA production, with three distinct growth media (Tryptic, MRS, and Mineral medium) assessed for their efficiency in polymer yield. Characterization of γ-PGA was conducted through FT-IR, HPLC, and GC-MS analyses. FT-IR spectroscopy confirmed the presence of characteristic functional groups such as carbonyl, amide, and hydroxyl groups. HPLC and GC-MS analyses provided insights into the polymer’s purity and molecular composition, highlighting components like methyl esters, hexanoic acid, and monomethyl esters. Furthermore, the study quantified γ-PGA production during a four-day shake flask fermentation period. These findings contribute significantly to bacterial characterization, optimization of fermentation processes, and the exploration of γ-PGA’s potential as an antibacterial agent. Future research directions include refining purification techniques to enhance γ-PGA’s antibacterial efficacy and expanding its applications across various fields.

## Linked entities

- **Chemicals:** hexanoic acid (PubChem CID 8892)
- **Species:** Bacillus subtilis (taxon 1423)

## Full-text entities

- **Chemicals:** methyl esters (-), Poly-gamma-Glutamic Acid (MESH:C511775), hexanoic acid (MESH:C037652), polymer (MESH:D011108)
- **Species:** Bacillus subtilis (species) [taxon 1423]

## Full text

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## Figures

8 figures with captions in the complete paper: https://tomesphere.com/paper/PMC12846282/full.md

## References

56 references — full list in the complete paper: https://tomesphere.com/paper/PMC12846282/full.md

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Source: https://tomesphere.com/paper/PMC12846282