| Title: | The physiological effect of heavy metals and volatile fatty acids on Methanococcus maripaludis S2 |
| Author(s): | Abdel Azim A; Rittmann SKR; Fino D; Bochmann G; |
| Address: | "1Institute for Environmental Biotechnology, IFA Department Tulln, University of Natural Resources and Life Sciences, Vienna, Austria. ISNI: 0000 0001 2298 5320. GRID: grid.5173.0 2Archaea Physiology & Biotechnology Group, Archaea Biology and Ecogenomics Division, Department of Ecogenomics and Systems Biology, Universitat Wien, Althanstrasse 14, 1090 Vienna, Austria. ISNI: 0000 0001 2286 1424. GRID: grid.10420.37 3Department of Applied Science and Technology (DISAT), Politecnico di Torino, Turin, Italy. ISNI: 0000 0004 1937 0343. GRID: grid.4800.c 4Center for Sustainable Future Technologies, Istituto Italiano di Tecnologia, Turin, Italy. ISNI: 0000 0004 1764 2907. GRID: grid.25786.3e" |
| DOI: | 10.1186/s13068-018-1302-x |
| ISSN/ISBN: | 1754-6834 (Print) 1754-6834 (Electronic) 1754-6834 (Linking) |
| Abstract: | "BACKGROUND: Methanogenic archaea are of importance to the global C-cycle and to biological methane (CH(4)) production through anaerobic digestion and pure culture. Here, the individual and combined effects of copper (Cu), zinc (Zn), acetate, and propionate on the metabolism of the autotrophic, hydrogenotrophic methanogen Methanococcus maripaludis S2 were investigated. Cu, Zn, acetate, and propionate may interfere directly and indirectly with the acetyl-CoA synthesis and biological CH(4) production. Thus, these compounds can compromise or improve the performance of M. maripaludis, an organism which can be applied as biocatalyst in the carbon dioxide (CO(2))-based biological CH(4) production (CO(2)-BMP) process or of methanogenic organisms applied in anaerobic digestion. RESULTS: Here, we show that Cu concentration of 1.9 micromol L(-1) reduced growth of M. maripaludis, whereas 4.4 and 6.3 micromol L(-1) of Cu even further retarded biomass production. However, 1.0 mmol L(-1) of Zn enhanced growth, but at Zn concentrations > 2.4 mmol L(-1) no growth could be observed. When both, Cu and Zn, were supplemented to the medium, growth and CH(4) production could even be observed at the highest tested concentration of Cu (6.3 micromol L(-1)). Hence, it seems that the addition of 1 mmol L(-1) of Zn enhanced the ability of M. maripaludis to counteract the toxic effect of Cu. The physiological effect to rising concentrations of acetate (12.2, 60.9, 121.9 mmol L(-1)) and/or propionate (10.3, 52.0, 104.1 mmol L(-1)) was also investigated. When instead of acetate 10.3 mmol L(-1) propionate was provided in the growth medium, M. maripaludis could grow without reduction of the specific growth rate (micro) or the specific CH(4) productivity (qCH(4)). A combination of inorganic and/or organic compounds resulted in an increase of micro and qCH(4) for Zn/Cu and Zn/acetate beyond the values that were observed if only the individual concentrations of Zn, Cu, acetate were used. CONCLUSIONS: Our study sheds light on the physiological effect of VFAs and heavy metals on M. maripaludis. Differently from micro and qCH(4), 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 CH(4) 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 CO(2)-BMP. Finally, we propose a possible mechanism for acetate uptake into M. maripaludis supported by in silico analyses" |
| Keywords: | Acetate Archaea Closed batch Copper Metabolism Methanogen Propionate Zinc; |
| Notes: | "PubMed-not-MEDLINEAbdel Azim, Annalisa Rittmann, Simon K-M R Fino, Debora Bochmann, Gunther eng England 2018/11/10 Biotechnol Biofuels. 2018 Nov 2; 11:301. doi: 10.1186/s13068-018-1302-x. eCollection 2018" |
