[Computational fluid dynamics simulation of different impeller combinations in high viscosity fermentation and its...

Area of Science:

• Biotechnology
• Chemical Engineering
• Microbial Fermentation

Background:

• Welan gum, a microbial exopolysaccharide, requires high aerobic and viscous conditions for production by Alcaligenes sp.
• Agitator design significantly impacts fermentation efficiency, especially for viscous microbial broths.

Purpose of the Study:

• To investigate the influence of different impeller combinations on fermentation performance in a welan gum bioreactor.
• To identify optimal impeller configurations for enhanced welan gum production.

Main Methods:

• Computational fluid dynamics (CFD) numerical simulations were employed to analyze velocity, shear rate, and gas holdup.
• Six distinct impeller combinations were simulated and evaluated.
• The top three performing impeller combinations were tested in actual welan fermentation trials.

Main Results:

• The MB-4-6 impeller combination demonstrated superior performance in maintaining dissolved oxygen levels and fluid velocity.
• Fermentation trials using the MB-4-6 combination resulted in a 13% increase in welan gum content.
• A notable increase in the viscosity of the final welan gum product was observed.

Conclusions:

• Impeller configuration is a critical factor for optimizing welan gum fermentation.
• The MB-4-6 impeller combination offers significant advantages for enhancing welan gum yield and product properties.