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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. [ABSTRACT FROM AUTHOR]

Foxtail millet (FM) and green banana (GB) are rich in health-promoting nutrients and bioactive substances, like antioxidants, dietary fibers, and various essential macro and micronutrients. Utilizing GB and FM flour as prebiotics is attributed to their ability to support gut health and offer multiple health benefits. The present study aimed to evaluate the impact of incorporating 10% GB flour (GBF) and different proportions (10–40%) of FM flour (FMF) on the prebiotic potential, antioxidant, nutrient, color, cooking quality, water activity and sensory attributes of noodles. The prebiotic potential, antioxidant, and nutrient of the produced noodles were significantly improved by increasing the levels of FMF. Sensorial evaluation revealed that noodles containing 30% FMF and 10% GBF attained comparable scores to the control sample. Furthermore, the formulated noodles exhibited significantly (p < 0.05) higher levels of protein, essential minerals (such as iron, magnesium, and manganese), dietary fiber (9.37 to 12.71 g/100 g), total phenolic compounds (17.81 to 36.35 mg GA eq./100 g), and total antioxidants (172.57 to 274.94 mg AA eq./100 g) compared to the control. The enriched noodles also demonstrated substantially (p < 0.05) increased antioxidant capacity, as evidenced by enhanced DPPH and FRAP activities, when compared to the control noodles. Overall, the incorporation of 30% FMF and 10% GBF led to a noteworthy improvement in the nutritional and antioxidant qualities of the noodles, as well as the prebiotic potential of the noodles with regard to L. plantarum, L. rhamnosus, and L. acidophilus. The implementation of this enrichment strategy has the potential to confer a multitude of health advantages. [ABSTRACT FROM AUTHOR]

Biosurfactants are naturally occurring compounds synthesized by micro-organisms that increasingly attract attention due to both their living area and application in various industries. In this study, we explore and characterize a novel bacterium, Enterobacter quasihormaechei strain BDIFST24001, isolated for its ability to produce rhamnolipid biosurfactants, with the aim of facilitating oil remediation processes. The isolation of this bacterium was carried out using Luria-Bertani (LB) broth media from environmental samples collected from oil-contaminated sites in Dhaka City. Screening tests, including the oil spreading method and drop collapse assay, were conducted to identify potential biosurfactant-producing strains, leading to the selection of E. quasihormaechei strain BDIFST24001 based on its favourable performance. Subsequent molecular identification revealed a high similarity of the strain's 16S rRNA gene to E. quasihormaechei , which was corroborated through phylogenetic analysis. Further analysis of the biosurfactant produced by this strain indicated its rhamnolipid nature, as confirmed by FT-IR spectroscopy. The rhamnolipids exhibited promising surface-active properties, including a significant reduction in surface tension and emulsification activity, as evidenced by surface tension measurements and emulsification index assays. Optimization studies revealed that the optimal conditions for rhamnolipid production by E. quasihormaechei strain BDIFST24001 were a temperature of 37 °C, pH 10.0 and salinity of 4 %. The rhamnolipids produced by this strain demonstrated effective oil remediation capabilities, as observed through controlled experiments using petrol oil. The rhamnolipids effectively reduced the surface tension of the oil-water interface, facilitating the dispersion and emulsification of the oil phase in water. Overall, our findings highlight the potential of E. quasihormaechei strain BDIFST24001 as a promising candidate for biosurfactant-mediated oil spill cleanup and environmental remediation efforts., Competing Interests: The authors stated that they have no identifiable financial conflicts of interest or personal relationships that could potentially bias the results reported in this paper., (Copyright © 2024 The Authors.)