Microbial Diversity Research of Produced Water from Daqing Oil Reservoir after Polymer Flooding

DNA was extracted from four oil well samples in Daqing oil reservoir after polymer flooding. A 16S rDNA clone library was constructed by PCR amplification applying universal primers, cloned in E.coli and subsequently characterized by amplified rDNA restriction analysis (ARDRA). 298 clones were obtained and classified into 22 different operational taxonomic units (OTUs). Four OTUs occupied 78.18 percent of the 16S rDNA clone library. Nine OTUs have only one clone. At the same time, the microbial diversity of the 16S rDNA clone library was evaluated by coverage value (C), Shannon-Weiner index (H) and Evenness index (E). Phylogenetic analysis showed that the dominant members of the library were affiliated with the Alphaproteobacteria (20.47%), the gammaproteobacteria (23.81%), the Deltaproteobacteria (32.21%) and the uncultured bacteria (21.16%). Pseudomonas and Acinetobacter which have the connection with biodegradation of hydrocarbon and production of surfactant occupied 17.79% and 6.02% in the clone library, respectively.