Long-chain fatty acids degradation by Desulfomonile species, proposal of “Candidatus Desulfomonile palmitatoxidans” and emended description of the genus Desulfomonile

A sulfate-reducing culture was enriched from anaerobic granular sludge using palmitate as the sole carbon and energy source. The culture was dominated by Desulfomonile-like bacterium (92 % relative abundance of the bacterial community) that showed a collar-like cell wall invagination, a distinct morphological feature of the Desulfomonile genus. Based on their average nucleotide identity (ANI, 77 %), we propose a novel species, designated as “Candidatus Desulfomonile palmitatoxidans”. A comparison of short-, medium- and long-chain fatty acid degradation by HP culture and D. tiedjei strain DCB-1 showed that both cultures degrade butyrate, caprylate, palmitate and stearate coupled to sulfate reduction, whereas oleate was only utilized by HP culture.