From batch to fed-batch and to continuous packed-bed reactors: Lipase-catalyzed esterifications in low viscous...

Area of Science:

• Biocatalysis
• Chemical Engineering
• Green Chemistry

Background:

• Deep Eutectic Solvents (DES) offer tunable properties for biocatalytic applications.
• Integrating DES with phosphate buffer (100 mM, pH 7) as a cosolvent (10% v/v) is novel for bioreactor systems.
• Lipase-catalyzed esterification of substrates with differing polarities necessitates effective solvent systems.

Purpose of the Study:

• To investigate the efficacy of DES-water mixtures in fed-batch and packed-bed bioreactors for biocatalysis.
• To optimize substrate flow rate for maximum conversion in fed-batch operations.
• To evaluate the productivity and biocatalyst stability in continuous flow systems.

Main Methods:

• Utilized lipase-catalyzed esterification of glycerol and benzoic acid.
• Employed fed-batch and packed-bed bioreactor configurations.
• Incorporated Deep Eutectic Solvents (DES) with phosphate buffer as a cosolvent system.
• Analyzed substrate flow rate, conversion, productivity, and biocatalyst stability over time.

Main Results:

• Achieved a maximum conversion of 90% in the fed-batch bioreactor at a substrate flow rate of 0.01 mL/min.
• Fed-batch operation enhanced conversion by 59% compared to batch mode.
• Continuous bioreactor with media recirculation reached 67% conversion over 7 cycles.
• Biocatalyst stability in the packed-bed bioreactor showed only a 2% decrease over 10 days.

Conclusions:

• Low viscosity DES-water mixtures are highly promising for continuous biocatalytic processes.
• The developed system demonstrates efficient esterification with enhanced conversion and stability.
• This approach offers a sustainable and effective alternative for biocatalytic esterification reactions.