Comprehensive analysis and comparison of protein, carbohydrate, polyhydroxybutyrate and fatty acid composition of four methanotrophic populations. Maxcromolecules from methanotrophs

Methanotrophic bacteria can metabolize methane to produce a variety of industrially valuable compounds, while decreasing the amount of this potent greenhouse gas in the atmosphere. We characterized the macromolecular composition of four different methanotrophic cultures dominated by Methylococcus capsulatus, Methylosinus trichosporium, Methylocystis parvus or Methylomonas methanica, respectively. The cultures were evaluated and compared in terms of growth, methane utilization and biomass composition. Total protein, polyhydroxybutyrate (PHB), fatty acid contents and elemental composition of the biomasses were analysed in both nitrogen excess and nitrogen limiting culturing conditions. Additionally, amino acid and elemental composition as well as carbohydrate content of four different methanotrophs were determined. Amino acid, fatty acid and carbohydrate compositions supports well with other common nutrient sources, thus the protein rich methanotrophic biomass is suitable for example as supplement for animal feed. Futhermore, methanotrophs are excellent biopolymer producers. This work provides a comprehensive comparison of the macromolecular composition of different methanotrophs under methane cultivation and thus guidance for choosing the appropriate consortia for different industrial applications.