Exponential fed-batch strategy for enhancing biosurfactant production by Bacillus subtilis

Area of Science:

• Biotechnology
• Microbial Fermentation
• Bioprocess Engineering

Background:

• Surfactin, a biosurfactant produced by Bacillus subtilis, has various industrial applications.
• Maldex-15, an industrial byproduct from high fructose corn syrup manufacturing, offers a low-cost substrate.
• Conventional batch fermentation limits efficient surfactin production.

Purpose of the Study:

• To optimize surfactin production using Bacillus subtilis BDCC-TUSA-3.
• To investigate the conversion of Maldex-15 into surfactin via fed-batch fermentation.
• To establish a cost-effective commercial surfactin production process.

Main Methods:

• Utilized Bacillus subtilis BDCC-TUSA-3 in a conventional batch process.
• Implemented exponential fed-batch fermentation, feeding Maldex-15 and nutrients based on bacterial growth rate.
• Conducted five fermentation runs with varying Maldex-15 quantities to maximize yield and productivity.

Main Results:

• Achieved high surfactin yield (36.1 g/L) and cell biomass (31.8 g/L) within 12 hours.
• Maximized results with 204 g Maldex-15, demonstrating efficient substrate conversion.
• Obtained a substrate yield of 0.272 g/g and volumetric productivity of 2.58 g/L/h.

Conclusions:

• Exponential fed-batch fermentation significantly enhances surfactin production.
• Maldex-15 is a viable and cost-effective substrate for commercial surfactin manufacturing.
• The developed bioprocess confirms the potential for economical, large-scale surfactin production.