Recent research led by Spencer A. Lee from the BioDiscovery Institute and the Department of Biological Sciences at the University of North Texas has revealed significant advancements in the capabilities of the methanotrophic bacterium Methylococcus capsulatus. This bacterium, known for its ability to consume methane (CH4) and convert it into valuable biomass, also has the unique potential to utilize carbon dioxide (CO2) as a carbon source. This dual functionality positions it as a promising candidate for biotechnological applications aimed at reducing greenhouse gases.
The study, published in the journal ‘mSphere’, highlights the role of carbonic anhydrases (CAs)—enzymes that facilitate the conversion of CO2 into bicarbonate and protons—in enhancing the growth and efficiency of M. capsulatus. The research identified five different isoforms of carbonic anhydrases in this bacterium, which are expressed in response to CO2 availability. The findings suggest that these isoforms have distinct, non-redundant roles in the organism’s metabolism.
One of the most striking results from the study is the development of an engineered strain of M. capsulatus that overexpresses specific carbonic anhydrases. This engineered strain demonstrated a remarkable 2.5-fold improvement in converting methane into bacterial biomass. As Lee noted, “The improvements to methanotroph-based product yields observed here are expected to reduce costs associated with CH4 conversion bioprocesses.” This could have significant implications for industries focused on sustainable energy solutions, particularly those looking to produce single-cell protein from natural gas or biogas derived from anaerobic digestion.
The ability to enhance carbon conversion efficiency not only contributes to more economically viable bioprocesses but also aligns with global efforts to mitigate greenhouse gas emissions. By optimizing the use of both methane and carbon dioxide, this research opens up new pathways for utilizing these gases in a more sustainable manner.
Overall, the advancements in M. capsulatus’s metabolic capabilities present exciting opportunities for the energy sector. As industries increasingly seek to reduce their carbon footprint, the application of engineered methanotrophic bacteria could play a crucial role in developing greener technologies and improving the economics of bio-based products. The study underscores the importance of understanding microbial metabolism in the quest for innovative solutions to climate change challenges.
