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

Extracellular poly-γ-glutamic acid (γ-PGA) produced by <i>Bacillus</i> species demonstrates significant antibacterial properties, positioning it as a promising candidate for diverse biomedical and industrial applications. This study focused on molecular identification of <i>Bacillus subtilis</i> using Polymerase Chain Reaction (PCR) and evaluated the initial production of γ-PGA from a novel biological source of <i>Bacillus subtilis</i>. 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.