How Specific Microbial Communities Benefit the Oil Industry: Significant Contribution of Methyl/Methanol-Utilising Methanogenic Pathway in a Subsurface Biogas Environment

Abstract

Methanogenesis is considered the main terminal process of subsurface anaerobic organic-matter degradation. Previous geochemical studies have reported CO₂-reducing and acetoclastic methanogenesis as the predominant subsurface methanogenic pathways for primary and secondary biogenic gas generation (i.e. in oil biodegradation or coalbed methane settings). In lab-scale experiments and microbiology literature, however, methanogens have been shown to be able to utilise a wider variety of substrates, typically containing methyl groups, i.e. dimethyl sulphide (DMS), methyl amines (e.g. TMA), formate, and methanol. Additional methanogenic substrates include CO and other primary alcohols and secondary alcohols (Whitman et al., 2006; Fig. 25.1). Here, we describe a volumetrically important natural biogenic gas field in which these methylotrophic pathways have contributed significantly to biomethane formation.