Bacillus circulans exopolysaccharide: Production, characterization and bioactivities

Area of Science:

• Microbiology
• Biochemistry
• Biotechnology

Background:

• Exopolysaccharides (EPS) are microbial polymers with diverse applications.
• Isolation of novel EPS-producing bacteria is crucial for biotechnological advancements.
• Coconut, a rich source of natural compounds, may harbor unique microbial communities.

Purpose of the Study:

• To isolate and identify an exopolysaccharide (EPS)-producing bacterium from coconut.
• To optimize EPS production using Response Surface Methodology (RSM).
• To characterize the chemical composition and evaluate the biological activities of the produced EPS.

Main Methods:

• Bacterial isolation from coconut slimy layer.
• 16S rDNA sequencing for bacterial identification.
• Optimization of EPS production using Box-Behnken design (RSM) with varying sucrose concentrations.
• High-Performance Liquid Chromatography (HPLC) and Nuclear Magnetic Resonance (NMR) for EPS composition analysis.
• In vitro assays for antioxidant, anti-inflammatory, anti-tumor, anti-bacterial, and anti-fungal activities.

Main Results:

• Bacillus circulans was identified as the EPS-producing bacterium.
• EPS production increased with sucrose concentration, reaching 1.09 mg/ml under optimized conditions.
• HPLC and NMR analyses confirmed the EPS is composed of glucose, mannose, fructose, verbascose, and galactose.
• The B. circulans EPS exhibited significant antioxidant, anti-inflammatory, and anti-tumor activities.
• No appreciable anti-bacterial or anti-fungal activity was observed.

Conclusions:

• Bacillus circulans isolated from coconut is a promising source of exopolysaccharides.
• Optimized production using sucrose significantly enhances EPS yield.
• The characterized EPS possesses valuable bioactive properties, particularly antioxidant, anti-inflammatory, and anti-tumor effects.
• Further research into the therapeutic potential of this bacterial EPS is warranted.