Segmented flow is controlling growth of catalytic biofilms in continuous multiphase microreactors

Area of Science:

• Biochemical Engineering
• Microfluidics
• Biocatalysis

Background:

• Biofilm reactors face mass transfer limitations due to excessive biofilm growth, hindering performance.
• Fluidic conditions significantly influence biofilm structure and overall reactor efficiency.

Purpose of the Study:

• To investigate the impact of aqueous-air segmented flow on biofilm structure and mass transfer in microreactors.
• To develop a method for forming robust, high-performance biofilms in continuous microreactors.

Main Methods:

• A three-step method involving single-phase flow, air-segment introduction for biofilm removal, and segmented flow for mature biofilm formation.
• Confocal laser scanning microscopy to analyze biofilm structure and growth.
• Demonstration using styrene epoxidation catalyzed by Pseudomonas sp. strain VLB120ΔC.

Main Results:

• Segmented flow promotes robust biofilm development with a 3-4 fold increase in growth rate and faster surface coverage (95% in 24h).
• Mature biofilms exhibited a more compact structure (roughness coefficient <1) compared to single-phase flow.
• Volumetric productivity for styrene epoxidation increased from 11 to 46 g L tube (-1) day(-1) with optimized air flow rate.

Conclusions:

• Aqueous-air segmented flow effectively controls biofilm structure and mitigates mass transfer limitations in microreactors.
• The developed method enables the formation of robust catalytic biofilms with enhanced growth rates and improved reactor performance.
• Interfacial forces in segmented flow can be utilized to optimize cell attachment and adaptation for superior biofilm reactor design.