A novel gas-phase bioreactor for CH4 biodegradation and bioconversion

Yan-Yu Chen (陳彥妤)1, 2, Katsutoshi Hori 2

1 Department of Chemical Engineering, National Chung Hsing University.

2 Department of Biotechnology, Graduate School of Engineering, Nagoya University.

In response to the urgent need to address environmental concerns such as climate change and global warming, the global target for net carbon emissions by 2050 has led to a rapid development of innovative technologies. Among these, bioprocessing and bioengineering have emerged as potential solutions for carbon capture, particularly from gas-phase sources, offering alternatives to the high-carbon processes prevalent in the conventional chemical industry. Conventional bioprocessing, typically conducted in water-based environments, faces challenges due to the low solubility of gases in water, requiring energy-intensive methods such as stirring and bubbling.

To address this issue, the novel "gas-phase bioreactor" has been developed, representing a significant shift in bioprocessing paradigms. This reactor uses immobilized microbial cells to catalyze gaseous substrates, eliminating the need for an aqueous phase. This approach not only conserves water, but also significantly reduces energy consumption. The core technology, the Inverse Membrane Bioreactor (IMBR), enables the efficient conversion of methane (CH4) to methanol (CH3OH) through direct gas-to-liquid bioconversion. Continuous CH3OH production has been successfully maintained in the IMBR for over 72 hours, achieving a productivity rate of 0.88 mmol L-1 h-1, which exceeds existing membrane bioreactor benchmarks.

In addition, this reactor enables unique microbial metabolic pathways in gas-phase reactions, leading to the production of valuable co-products such as xanthines without genetic modification. This technology not only provides a sustainable solution for methane mitigation, but also serves as a versatile platform for multiple environmental and industrial applications. The "gas-phase bioreactor" aligns with global environmental goals and demonstrates the potential of bioprocessing to foster a more sustainable future. This innovative approach is a testament to the evolving landscape of environmental technology that prioritizes energy efficiency and sustainability.