Exploring the purification, characterization, and industrial applications of Exopolysaccharide (EPS) from Bacillus amyloliquefaciens strain BDIFST240014

Background: Exopolysaccharides (EPS) derived from microbial sources hold great promise for various industrial applications due to their biodegradability and diverse biological activities.

Methods and results: In this study, EPS was isolated and characterized from Bacillus amyloliquefaciens strain BDIFST240014, a Gram-positive bacterium known for its robust EPS production. Taxonomic classification was confirmed through 16 S rRNA gene sequencing. We optimized the growth conditions for EPS production, yielding a maximum of approximately 74.81 mg/L after 48 h of incubation at 37 °C. UV-vis and FTIR spectroscopy were used to characterize the EPS, revealing key functional groups indicative of its polysaccharide nature. The EPS contained total carbohydrate and protein contents of 841.234 µg/5 mg and 630.54 µg/5 mg, respectively, along with a potent water holding capacity (WHC) of 103.31% and oil holding capacity (OHC) of 106.78%, underscoring its potential as a multifunctional biopolymer. Antimicrobial assays demonstrated significant activity against both Gram positive and Gram negative pathogens, including S. aureus, B. subtilis, E. coli, and S. typhi. Antioxidant assays confirmed its potent DPPH radical scavenging activity (71.52%) and Fe³⁺ reducing capacity. Furthermore, emulsification studies showed its efficacy with various oils (coconut oil, soybean oil, sunflower oil, olive oil) and a hydrocarbon (n-hexane), with the highest emulsification indices (E1 and E24) of 60.78% and 60.39%, respectively, against coconut and sunflower oils. Notably, the EPS selectively promoted the growth of probiotic strains while not enhancing the growth of pathogenic bacteria, highlighting its prebiotic potential.

Conclusions: These findings suggest that EPS from B. amyloliquefaciens BDIFST240014 is a promising candidate for diverse industrial and biomedical applications.