Investigating the phylogeny of hydrogen metabolism by comparative genomics: Horizontal gene transfer

Abstract

MiThe phylogenetic analysis based on molecular characteristics indicates that lithotrophic metabolism was followed by phototrophy. Hydrogen (H2) metabolism is a signature of such environments. This property is prominent among organisms found in geothermal conditions and in deep aquifers. H2 is generated readily by abiotic mechanisms where the terminal electron acceptor is likely to be the limiting factor. In the post-fossil fuel era, H2 has in fact emerged as a strong contender for future fuel. It is thus important to understand the molecular mechanisms which lead to H2 production and associated biological systems. These can help to comprehend issues such as sustainability, environmental emissions and energy security. Comparative genomic analysis reveals events of horizontal transfer of genes of H2 metabolism among taxonomically diverse organisms. This offers an opportunity to identify those genomes which can be tailored for transforming presently ‘non’-H2 producers into producers. This also suggests that naturally occurring events can be mimicked to provide future fuel H2.