| This paper was mainly concerned in the methanogenic archaea during the anaerobic crude oil degradation and production of methane. The results concluded: (1) isolated 8 hydrotropic methanogenic archaea (named CC-1,CC-2,CC-3,ZC-2,ZC-3,ZC-4,ZC-5,ZC-6)and 1 methyltropic methanogenic archaea(named ZC-1).Phylogenetic analysis of 16S rRNA gene indicated strain CC-1 was most closely related to Methanococcus maripaludis(100%),strain CC-3 was most closely related to Methanocalculus pumilus(99%), strains ZC-2,ZC-3,ZC-6 were all most related to Methanoculleus palmaeoli(97.4-97.6%), and strain ZC-2 was identical to strain ZC-6 and showed 99% similarity to strain ZC-3, strain ZC-1 was most related to Methanosaeta harundinacea (90.6%) and was most related to M.thermophila (76.4%) by analysis of inferred amino acids of partial mcrA gene. (2) based on further research on the physiological and biochemical characteristics of strain ZC-1, a novel taxon is proposed and named Methanotheromicrococcus shengliense gen.nov, sp.nov. (3) Steady hydrotropic and metylothopic methanogenic enrichment were obtained by inoculating oil-production water, but steady acetatrophic methanogen enrichment was not obtained. Methane was producted from anaerobic incubation at 55℃with crude oil as a solo carbon source and with hydrotropic methanogenic enrichment as inculator. The 13δCPDB of methane was adjacent to reference of biogas. There were obvious "convex" from the gas chromatograms of saturated hydrocarbon of crude oil after microbial degradation.The content of n-alkane decreased, and the content of unknown compounds increased, some peaks of unknown compounds were much more higher than n-alkane. The long-chain alkanes of crude oil were anaerobicly degradated predominatly, and then there were mid-short chain alkanes, There are also different degradation degrees between duplicates.
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