In vitro evaluation of new functional properties of poly-Ɣ-glutamic acid produced by Bacillussubtilis D7

We investigated the functionality of poly-c-glutamic acid (Ɣ-PGA), which is produced by Bacillus subtilis D7, for its potential applications in medicine and cosmetics. The c-PGA had angiotensin-converting enzyme (ACE) inhibition activity. ACE inhibition activity was dependent on the Ɣ-PGA concentration; the highest ACE inhibition activity was observed at 1.25 mg/l of c-PGA.IC50 (0.108 mg/ml) of the Ɣ-PGA was lower than that of standard ACE inhibitory drug, N-[(S)-mercapto-2-methylpropionyl]-L-proline (0.247 mg/ml). The Ɣ-PGA also had water-holding capacity and hygroscopicity. Furthermore, the c-PGA inhibited growth of some pathogenic bacteria, including Listeria monocytogenes, Salmonella typhimurium, Staphylococcus aureus, Klebsiella pneumonia and Esherichia coli. The Ɣ-PGA exhibited a good metal adsorption capacity; Cr (VI) adsorption capacity of Ɣ-PGA increased with decreasing pH, and the maximal adsorption was observed at pH 2. Our results suggest that Ɣ-PGA may be expected to be widely applied in cosmetics, biomedical and environmental industries with the feature of being less harmful to humans and the environment.