An innovative membrane bioreactor for methane biohydroxylation

Area of Science:

• Biotechnology
• Chemical Engineering
• Environmental Microbiology

Background:

• Microbial methane hydroxylation is crucial for converting methane into valuable products.
• Traditional methods face challenges with mass transfer limitations and safety concerns regarding explosive gas mixtures.
• Methylosinus trichosporium OB3b is a well-studied methanotroph capable of methane oxidation.

Purpose of the Study:

• To develop and demonstrate an efficient and safe membrane bioreactor (MBR) for microbial methane hydroxylation.
• To improve the mass transfer of gaseous substrates (methane and oxygen) in the bioreaction.
• To achieve high productivity in methane hydroxylation using Methylosinus trichosporium OB3b.

Main Methods:

• Development of a novel MBR system coupling a bioreactor with two gas/liquid macroporous membrane contactors.
• Operation of the MBR in fed-batch mode for controlled substrate supply.
• Cultivation of Methylosinus trichosporium OB3b for methane hydroxylation.

Main Results:

• Demonstrated feasibility and reproducibility of the novel MBR process.
• Achieved a mass transfer rate twice that of a conventional batch reactor.
• Reached a high productivity of 75±25 mg methanol/(g dry cell·h), significantly outperforming previous MBRs.
• Avoided the risk of explosive gas mixture formation inherent in bubble-sparger systems.

Conclusions:

• The developed MBR offers an efficient and safe platform for microbial methane hydroxylation.
• Macroporous membrane contactors enhance gas-liquid mass transfer, leading to improved productivity.
• This MBR technology presents a promising alternative to conventional bioreactors for methane conversion applications.