Screening of Methanotrophic Strain for Scale Applications: Methane Emission Reduction and Resource Utilization

Methanotrophs hold significant potential in global methane mitigation and resource recovery. However, the limited rate of cell proliferation remains a significant constraint for large-scale applications. Therefore, screening efficient methanotrophic strains that are suitable for industrial applications to mitigate methane and exploring potential methane resource utilization pathways are of great importance for sustainable development. Gradient dilution and the streak plate method were employed to isolate methanotrophic strains from a previously domesticated methane-oxidizing microbial consortium. We isolated a highly efficient strain, M6, which exhibited a 230% increase in growth rate compared to the laboratory model strain Methylocystis bryophila (M. bryophila). Taxonomic analysis revealed that strain M6 is classified as Methylocystis parvus. Genomic data indicated a diverse range of metabolic functions. In addition to utilizing methane, strain M6 can also utilize citrate to generate energy and intermediate products, addressing issues related to insufficient methane supply or low methane mass transfer efficiency. Metabolic adaptability ensures the stability of its application. The optimal cultivation conditions for strain M6 were determined, characterized by mild and easily implementable parameters. Based on the analysis of the genome and metabolic pathways, strain M6 exhibits potential for the synthesis of bioproducts, such as proteins, lipids, and polyhydroxyalkanoates (PHAs), with the fermentation process not requiring cost-intensive carbon sources, making it both economical and sustainable.