Investigation Of Carbon Cycle Related Microbial Diversity In Sludge Treatment Reed Beds

The sludge treatment reed bed(STRB) systems are considered as an eco-friendly technology for treatment of excess activated sludge. In order to explore the microbial function and carbon recycling processes in STRB, the authors investigated the diversity of methanogenic archaea and methanotroph by using denaturing gradient gel electrophoresis(DGGE) which came from different seasons.The clustering analysis results from the fingerprints of DGGE showed that the communities of methanogenic archaea were different in those samples that were taken from different reed beds during the same period, indicating that aeration had an influence on methanogenic archaeal community structure. In addition, the communities of methanogenic archaea were also different in the same reed bed at different periods, demonstrating that season and condition of reed contributed to community structure. The diversity index of the sludge samples from the aeriferous reed bed were lower than that from the non-aeriferous reed bed, indicating that aeration will inhibit the activities of methanogenic archaea in reed bed. In the aeriferous reed bed, the diversity kept increasing from spring to autumn and decreased to winter. However, diversity of non-aeriferous reed bed gradually increased with the extension of stabilization period. A total of 12 bands were successfully sequenced for methanogenic archaea, they were affiliated with Methanosarcina and Methanomicrobium.A total of 21 bands were successfully sequenced for methanotroph in STRB, they were affiliated with the genus: Methylocaldum, Methylomicrobium, Methylococcus, Methylosarcina,Methylomonas, Methylocystis, Methylosinus. The communities of type I methanotroph were similar in those samples that were taken from different seasons in the same reed bed, but they were different in those samples that were taken from different reed beds during the same period, demonstrating that season and aeration contributed to the community structure. For type II methanotrophs, community structure had no obvious relation with seasonal variation and the ventilation structure.For type I methanotrophs, the diversity index of the sludge samples from the aeriferous reed bed were higher than those that from the non-aeriferous reedbed, which increased the chance of methane oxidation.