The physiological effect of heavy metals and volatile fatty acids on Methanococcus maripaludis S2.

Our study sheds light on the physiological effect of VFAs and heavy metals on M. maripaludis. Differently from µ and qCH4, MER was not influenced by the presence of these compounds. This indicated that each of these compounds directly interacted with the C-fixation machinery of M. maripaludis. Until now, the uptake of VFAs other than acetate was not considered to enhance growth and CH4 production of methanogens. The finding of propionate uptake by M. maripaludis is important for the interpretation of VFA cycling in anaerobic microenvironments. Due to the importance of methanogens in natural and artificial anaerobic environments, our results help to enhance the understanding the physiological and biotechnological importance with respect to anaerobic digestion, anaerobic wastewater treatment, and CO2-BMP. Finally, we propose a possible mechanism for acetate uptake into M. maripaludis supported by in silico analyses.