Exploring the capabilities of Methylotuvimicrobium alcaliphilum 20Z to produce exopolymeric substances from methane

Methylotuvimicrobium alcaliphilum 20Z is a haloalkaliphilic methanotroph with promising biotechnological potential for methane valorization. However, its ability to produce extracellular polymeric substances (EPS) from methane remains poorly characterized. In this study, we evaluated EPS production by M. alcaliphilum 20Z after one week of cultivation under 14 combinations of temperature, pH, and methane availability. pH emerged as the primary factor controlling EPS synthesis, with neutral to slightly acidic conditions (pH 6-8.5) supporting the highest EPS and biomass levels, whereas alkaline treatments (pH 11) strongly inhibited growth and total EPS production. Higher methane concentrations (30% CH₄) further enhanced EPS formation. EPS matrices were consistently protein-rich, suggesting roles in adhesion and early biofilm stabilization. Transcriptomic analysis revealed coordinated upregulation of methane oxidation and C1-processing pathways under conditions favoring EPS production and growth. These findings identify environmental conditions that promote methane-derived exopolymer synthesis and highlight the potential of M. alcaliphilum 20Z as a platform for EPS-based bioprocesses.