Optimizing Exopolysaccharide Production by Bacillus subtilis Using Spoiled Fig and Grape

Area of Science:

• Biotechnology
• Microbiology
• Sustainable Bioprocessing

Background:

• Exopolysaccharides (EPSs) are valuable biopolymers with diverse applications.
• Bacillus subtilis is a known producer of EPSs.
• Utilizing waste materials as substrates for biopolymer production offers economic and environmental benefits.

Purpose of the Study:

• To enhance exopolysaccharides (EPS) production by Bacillus subtilis ES (OR501464).
• To evaluate spoiled grape and fig extracts as cost-effective substrates for EPS synthesis.
• To optimize nutritional factors influencing EPS production.

Main Methods:

• Isolation and identification of high-EPS producing bacterial strains.
• Optimization of production medium components (sucrose, NaNO3, Na2SO4, NaCl), temperature, and pH.
• Assessment of EPS production using spoiled grape and fig extracts with varying nutrient supplements.
• Partial characterization of EPS using GC-MS and FTIR spectroscopy.

Main Results:

• Bacillus subtilis ES (OR501464) was identified as a high-yield EPS producer.
• Optimal production medium yielded 4.7 g/L EPS with 4% sucrose, 0.1% NaNO3, 0.002% Na2SO4, and 2% NaCl at 30°C and pH 9.
• Spoiled grape extract supplemented with 2% NaCl increased EPS production to 4.357 mg/mL.
• Supplementation of spoiled fig or grape extract with 0.2 g/L Na2SO4 and 1 g/L NaNO3 enhanced EPS production.

Conclusions:

• Spoiled figs and grapes are viable, sustainable substrates for bacterial EPS production.
• Nutritional optimization significantly enhances EPS yield from these waste materials.
• This research supports eco-friendly bioprocessing for valuable biopolymer generation.