Methylotuvimicrobium alcaliphilum 20Z based biogas valorization strategy using salting-out process for simultaneous production of ectoine and sodium bicarbonate.

Methanotroph-based biogas conversion technology is gaining significant attention for its mild operating conditions and environmental benefits. Direct utilization of biogas, without removing CO2, can enable efficient CH4 utilization while conserving the energy typically required for CO2 separation, which demands substantial thermal energy. However, a key challenge lies in the substantial consumption of buffer solutions due to CO2 dissociation at high pH (8.9-9.1), which increases the operating costs. To overcome this limitation, a novel salting-out process is proposed to recover Na+ ions from NaOH solutions, integrated with ectoine production using Methylotuvimicrobium alcaliphilum 20Z. The proposed system incorporates a continuous cultivation system to simultaneously recover HCO3- ions generated during CO2 dissociation and Na+ ions introduced during the biological process. By establishing a multi-reaction system capable of converting CH4 and CO2 simultaneously, this study pioneers a pathway for the biogas-based production of high-value chemicals, offering significant advancements over existing technologies.