The Isolation Of The Methanogens And Analysis On Microbial Community Structure In Psychrophilic Anaerobic Environment

Psychrophilic anaerobic digestion is very important for the utilization of resource. The reseacher study the methanogens which play the key role in anaerobic digestion. PCR-DGGE method was applied to study samples from anaerobic digesters.Three novel strains of eurypsychrophile methanogens, LZ-6, DL-5, DL-4 were isolated from Nyingtri Tibet and Doilungdeqen County Tibet by using anaerobic cultivation techniques. Analysis of the 16S rDNA sequence revealed that the strain was phylogenetically related to Methanocorpusculum. Study the biological characteristic of strain LZ-6. Cells were irregular and coccus. Growth was observed with an optimum at 25℃. The catabolic substrates used included H2/CO2 and formate, but not acetate or methanol.Anaerobic digesters samples were collected with different months. After DNA extraction, the DNA was used as template to amplify 16S rRNA gene. Distinct differences were detected in fingerprint at band numbers, band patterns and denstities with different sampling months. Quantitative analyses by Quantity One software showed that there were four major types of bacterial community and archaea community structure in anaerobic digesters, including the end of autumn period, beginning autumn period, the end of winter period, beginning spring period. Typical bands were excised and sequenced. The sequences obtained were affiliated with Uncultured bacterium clone FLSED43 and Uncultured rumen bacterium clone YRC75 in bacterial community and Methanocorpusculum in archaea community.