Objectives: Methanotrophs are microorganisms that utilize methane as a carbon and energy source, playing a crucial role in the carbon cycle. Due to their high potential for single-cell protein (SCP) production, they are considered valuable candidates in biotechnological industries. This study aimed to investigate the enhancement of biomass production under aerobic and anaerobic methane conditions for three methanotrophic species-Methylococcus capsulatus (Bath), Methylomicrobium album BG8, and Methanoperedens nitroreducens-using in silico approach.
Materials and Methods: The genome-scale metabolic models of these microorganisms (iMcBath, iJV803, and iMN22HE) were reconstructed and analyzed using the COBRA Toolbox in the MATLAB environment. Target reactions for optimization were selected based on flux sensitivity analysis and a comprehensive literature review identifying key reactions in methane oxidation and nitrogen metabolism. Subsequently, Flux Balance Analysis (FBA) was performed to evaluate biomass flux under baseline and optimized conditions, and the results were comparatively assessed.
Results: After the applied metabolic modifications, the biomass flux of M. capsulatus, M. album, and M. nitroreducens increased by 2.28, 1.94, and 1.25-fold compared to their baseline states, respectively. Moreover, flux sensitivity and variability analyses indicated that the model predictions were robust against changes in substrate uptake rates.
Conclusion: Given the substantial increase in biomass yield of Methylococcus capsulatus (Bath), along with its established biotechnological relevance and available cultivation technology, it is recommended that the proposed metabolic modifications be experimentally validated to expand its potential industrial and bioprocess applications.