Characterization of novel extracellular polymeric substances produced by Bacillus velezensis P1 for potential biotechnological applications

Abstract Bacillus velezensis ( B. velezensis ) P1 released huge amount of exopolymeric substances (EPS), and its EPS was extracted and characterized. The extracted EPS strongly inhibited (88%–91%) the growth of two serious rice fungal pathogens. The main component of the EPS was protein (44%). Fourier transform infrared spectra of the EPS revealed a complex structure that contained sufficient negatively charged functional groups for the zeta potential of the compound to be highly negative (−33.83 mV). Scanning electron microscope images revealed plate‐like particles with smooth, clean surfaces. The EPS showed high degrees of whiteness (L* = 94.56) and crystallinity (87%), and was thermally stable up to 500°C. Flocculation activity in a kaolin dispersion was optimal at an EPS concentration of 12 mg L −1 . The EPS preferred an alkaline condition, with the highest flocculation activity (76%) observed at pH 10. The EPS produced by B. velezensis P1 could be a potential material for applying in agriculture and industry.