A well-mixed, polymer-based microbioreactor with integrated optical measurements

Area of Science:

• Biotechnology and Bioengineering
• Microfluidics and Lab-on-a-Chip Devices
• Microbial Cultivation and Bioprocessing

Background:

• Traditional microbial cultivation methods often lack precise control and real-time monitoring capabilities.
• There is a need for miniaturized, integrated systems for efficient microbial cell culture.
• Poly(methylmethacrylate) (PMMA) and poly(dimethylsiloxane) (PDMS) are suitable materials for microfluidic device fabrication.

Purpose of the Study:

• To design and fabricate a 150 microL microbioreactor for microbial cell cultivation.
• To integrate online monitoring sensors for pH, dissolved oxygen, and cell density.
• To evaluate the mixing and oxygenation performance and demonstrate cell growth capabilities.

Main Methods:

• Fabrication of the microbioreactor using poly(methylmethacrylate) (PMMA) and poly(dimethylsiloxane) (PDMS).
• Integration of magnetic stir bar for mixing and fluorescent sensors for real-time measurements.
• Use of optical transmission for cell density monitoring and computational fluid dynamics (CFD) for mixing analysis.
• Measurement of oxygen transfer coefficients (KLa) at varying stirring speeds.

Main Results:

• The microbioreactor achieved oxygenation values (KLa) ranging from 20-75/h with stirring speeds of 200-800 rpm.
• Demonstrated successful cultivation and growth of Escherichia coli, benchmarked against conventional methods.
• Showcased reproducible batch cultures of Saccharomyces cerevisiae, highlighting system flexibility.

Conclusions:

• The developed microbioreactor offers a robust platform for microbial cell culture with integrated monitoring.
• The system provides efficient mixing and oxygenation, crucial for microbial metabolism.
• This technology presents a promising, reproducible, and flexible alternative for microbial bioprocessing.