Characterization of a continuous agitated cell reactor for oxygen dependent biocatalysis

Area of Science:

• Biochemical Engineering
• Chemical Reaction Engineering
• Biocatalysis

Background:

• Biocatalytic oxidation reactions using molecular oxygen face challenges in continuous flow reactors due to low oxygen transfer rates.
• Efficient oxygen transfer is critical for scaling up aerobic biocatalytic processes.

Purpose of the Study:

• To investigate a novel continuous agitated cell reactor (ACR) for enhancing oxygen transfer in biocatalytic oxidation.
• To model the hydrodynamics of the ACR and evaluate its performance using glucose oxidase for glucose oxidation.

Main Methods:

• Developed and utilized a novel continuous agitated cell reactor (ACR) with ten interconnected cells and spring agitators.
• Employed tracer experiments to develop a hydrodynamic model of the ACR, describing it as tanks-in-series with back-mixing.
• Compared the steady-state conversion in the ACR with a stirred batch reactor to evaluate performance.

Main Results:

• The ACR demonstrated a significantly increased oxygen transfer rate due to intense mixing, with a volumetric oxygen transfer coefficient (k_La) of 344 h^-1, compared to 104 h^-1 in a batch reactor.
• The ACR achieved more than double the overall reaction rate for glucose oxidation compared to a batch reactor.
• The ACR exhibited complex hydrodynamic behavior, acting like two continuous stirred tank reactors (CSTRs) at low flow rates and ten CSTRs at high flow rates, yet conversion was minimally affected.

Conclusions:

• The novel agitated cell reactor (ACR) design effectively overcomes oxygen transfer limitations in continuous flow biocatalytic oxidations.
• The ACR offers a substantial improvement in reaction rates, making it a promising technology for industrial biocatalysis.
• The hydrodynamic complexity of the ACR did not impede its efficiency, highlighting its robustness.