Abstract

Thermophilic microbial diversity in production water from a high temperature, water-flooded petroleum reservoir of an offshore oilfield in China was characterized by enrichment and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis. Six different function enrichment cultures were cultivated one year, at 75°C DGGE and sequence analyses of 16S rRNA gene fragments were used to assess the thermophilic microbial diversity. A total of 27 bacterial and 9 archaeal DGGE bands were excised and sequenced. Phylogenetic analysis of these sequences indicated that 21 bacterial and 7 archaeal phylotypes were affiliated with thermophilic microbe. The bacterial sequences were mainly bonged to the genera Fervidobacterium,Thermotoga, Dictyoglomus, Symbiobacterium, Moorella, Thermoanaerobacter,Desulfotomaculum, Thermosyntropha, Coprothermobacter, Caloramator,Thermacetogenium, and the archaeal phylogypes were represented in the generaGeoglobus and Thermococcus, Methanomethylovorans, MethanothermobacterMethanoculleus and Methanosaeta. So many thermophiles were detected suggesting that they might be common habitants in high-temperature petroleum reservoirs. The results of this work provide further insight into the thermophilic composition of microbial communities in high temperature petroleum reservoirs.

Key words: Thermophilic microbial diversity, petroleum reservoir, denaturing gradient gel electrophoresis.