Marine methane-reduction mechanism

Anaerobic methane oxidation in marine sediments is coupled to sulphate reduction and is carried out by a consortium of methanotrophic archaea (ANME) and Deltaproteobacteria. However, the underlying biochemical pathway and electron-transfer mechanism between the two species has been difficult to determine. Jana Milucka et al. now demonstrate that this transformation involves the reduction of sulphate to elemental sulphur by ANME and disulphide disproportionation (simultaneous oxidation and reduction of a substance reacting with itself) by the Deltaproteobacterium — the latter process a previously unknown microbial sulphur transformation.