Methanobrevibacter boviskoreani JH1(T) growth on alcohols allows development of a high throughput bioassay to detect methanogen inhibition

Rumen methanogenic archaea use by-products of fermentation to carry out methanogenesis for energy generation. A key fermentation by-product is hydrogen (H(2)), which acts as the source of reducing potential for methane (CH(4)) formation in hydrogenotrophic methanogens. The in vitro cultivation of hydrogenotrophic rumen methanogens requires pressurised H(2) which limits the ability to conduct high-throughput screening experiments with these organisms. The genome of the hydrogenotrophic methanogen Methanobrevibacter boviskoreani JH1(T) harbors genes encoding an NADP-dependent alcohol dehydrogenase and a F(420)-dependent NADP reductase, which may facilitate the transfer of reducing potential from ethanol to F(420) via NADP. The aim of this study was to explore the anaerobic culturing of JH1(T) without pressurised H(2), using a variety of short chain alcohols. The results demonstrate that in the absence of H(2), JHI(T) can use ethanol, 1-propanol, and 1-butanol but not methanol, as a source of reducing potential for methanogenesis. The ability to use ethanol to drive CH(4) formation in JH1(T) makes it possible to develop a high throughput culture-based bioassay enabling screening of potential anti-methanogen compounds. The development of this resource will help researchers globally to accelerate the search for methane mitigation technologies for ruminant animals. Global emissions pathways that are consistent with the temperature goal of the Paris Agreement, rely on substantial reductions of agricultural greenhouse gasses, particularly from ruminant animals.