The sulphate-reducing bacteria strain H1 with the function for Hydrolysed Polyacrylamide (HPAM) degradation was isolated from a curing pot in the HPAM distribution station of Daqing Oil Field using the Hungate Anaerobic Technique. The isolates were characterised morphologically, physiologically, biochemically and molecularly. The pictures of the Atomic Force Microscope (AFM) have shown that this is a short bacillus with width 0.30?0.39 ?m and length 0.72-1.63 ?m, with flagellum and spores, and is gram negative and strictly anaerobic bacteria, which can reduce sulphate to H2S. Alignment of 16S Ribosomal DNA (rDNA) and 16S?23S rDNA intergenic spacer sequences suggests that this isolate was closely related to the Clostridium. Fatty acids were distributed at C12.0-C20,0, mostly at C14.0, C16.0 and C19:11ω12c, the content being 9.10%, 40.01% and 7.11%, respectively, i.e. 56.22% of all fatty acids. The isolate was identified as a new species belonging to fusobacterium, temporarily named Clostridium bifermentans H1. Analysis results of Infrared (IR) spectroscopy showed that the bacteria can use HPAM as the only carbon source, hydrolysing the amide to carboxyl group by the molecule chain amide hydrolysis, degrading the side chain and changing some function group, resulting in obviously decreased viscosity. Using GC-MS determined HPAM-degraded products of low molecular weight compounds were polyacrylamide fragments with duplet bonds, epoxy as well as carbonyl group, but most of them were acrylamide oligomer derivatives. The removing efficiency for HPAM reached 30.8%.
Keywords: HPAM degrading bacteria, identification, biodegradation, 16S rDNA, sulphate-reducing bacteria, hydrolysed polyacrylamide degradation