Scale-up of microbubble dispersion generator for aerobic fermentation

Area of Science:

• Biotechnology
• Chemical Engineering
• Microbiology

Background:

• Microbubble dispersion (MBD) generators enhance oxygen transfer in laboratory settings.
• Scaling up MBD technology for industrial aerobic fermentation requires validation.
• Saccharomyces cerevisiae (baker's yeast) fermentation is a key industrial aerobic process.

Purpose of the Study:

• To investigate the scale-up of a spinning-disk MBD generator for aerobic fermentation of Saccharomyces cerevisiae.
• To evaluate the efficiency of MBD in improving oxygen transfer and cell growth in larger fermentation volumes.
• To compare the energy consumption and operational costs of MBD versus conventional air-sparging systems.

Main Methods:

• A 1-L spinning-disk MBD generator was employed for 1-L and 50-L baker's yeast fermentations.
• Oxygen transfer was assessed by measuring the volumetric mass transfer coefficient (kLa).
• Cell mass yield and power consumption were compared between MBD and conventional air-sparging.

Main Results:

• The MBD generator effectively supplied microbubbles at a low agitation rate (150 rpm).
• MBD demonstrated improved oxygen transfer, although kLa values were comparable to conventional sparging at higher agitation.
• Cell mass yield was similar between MBD and conventional methods, but MBD consumed threefold less power per unit volume for similar product yield.

Conclusions:

• The MBD generator is a viable technology for scaling up aerobic fermentation of Saccharomyces cerevisiae.
• MBD technology offers significant potential for reducing energy consumption and operating costs in industrial aerobic fermentation.
• Further studies on larger volumes may yield even greater improvements in dissolved oxygen levels and kLa values.