Sorokin Dimitry Y, Abbas Ben, Merkel Alexander Y, Rijpstra W Irene C, Damsté Jaap S Sinninghe, Sukhacheva Marina V, van Loosdrecht Mark C M
Winogradsky Institute of Microbiology, Research Centre of Biotechnology, Russian Academy of Sciences, Moscow, Russia.
Department of Biotechnology, TU Delft, The Netherlands.
Int J Syst Evol Microbiol. 2015 Oct;65(10):3739-3745. doi: 10.1099/ijsem.0.000488. Epub 2015 Jul 29.
Two groups of haloalkaliphilic methanogenic archaea were dominating in enrichments from hypersaline soda lake sediments at pH 10. At moderate salt concentrations with formate or H2 as electron donor, methanogens belonging to the genus Methanocalculus were enriched, while at high salt concentrations with methylated substrates, a group related to Methanosalsum zhilinae was dominating. For both groups, several pure cultures were obtained including the type strains AMF2T for the Methanocalculus group and AME2T for the Methanosalsum group. The Methanocalculus group is characterized by lithoheterotrophic growth with either formate (preferable substrate) or H2 at moderate salinity up to 1.5-2 M total Na+ and obligate alkaliphilic growth with an optimum at pH 9.5. According to phylogenetic analysis, the group also includes closely related strains isolated previously from the low-salt alkaline Lonar Lake. The novel Methanosalsum group is characterized by high salt tolerance (up to 3.5 M total Na+) and obligate alkaliphilic growth with an optimum at pH 9.5. It has a typical methylotrophic substrate profile, utilizing methanol, methylamines and dimethyl sulfide (at low concentrations) as methanogenic substrates. On the basis of physiological and phylogenetic data, it is proposed that the two groups of soda lake methanogenic isolates are assigned into two novel species, Methanocalculus alkaliphilus sp. nov. (type strain AMF2T = DSM 24457T = UNIQEM U859T) and Methanosalsum natronophilum sp. nov. (type strain AME2T = DSM 24634T = NBRC 110091T).
在pH值为10的高盐碱性湖泊沉积物富集培养物中，有两组嗜盐碱产甲烷古菌占主导地位。在中等盐浓度下，以甲酸盐或氢气作为电子供体时，富集到了属于甲烷计算菌属的产甲烷菌，而在高盐浓度下，以甲基化底物作为电子供体时，一组与嗜盐碱甲烷盐菌相关的菌群占主导地位。对于这两组菌群，均获得了多个纯培养物，包括甲烷计算菌组的模式菌株AMF2T和嗜盐碱甲烷盐菌组的模式菌株AME2T。甲烷计算菌组的特征是在中等盐度（总钠离子浓度高达1.5 - 2 M）下以甲酸盐（首选底物）或氢气进行岩化异养生长，以及专性嗜碱生长，最适pH值为9.5。根据系统发育分析，该组还包括先前从低盐碱性的洛纳尔湖分离出的密切相关菌株。新的嗜盐碱甲烷盐菌组的特征是耐高盐（总钠离子浓度高达3.5 M）和专性嗜碱生长，最适pH值为9.5。它具有典型的甲基营养底物谱，利用甲醇、甲胺和二甲基硫醚（低浓度时）作为产甲烷底物。基于生理和系统发育数据，建议将这两组苏打湖产甲烷分离株归入两个新物种，即嗜碱甲烷计算菌（Methanocalculus alkaliphilus sp. nov.）（模式菌株AMF2T = DSM 24457T = UNIQEM U859T）和嗜钠嗜盐碱甲烷盐菌（Methanosalsum natronophilum sp. nov.）（模式菌株AME2T = DSM 24634T = NBRC 110091T）。
