Microbial community studies from different design of anaerobic ammonia oxidation reactors.

• Main Authors: Yu-chun Chiu, 邱榆鈞
• Other Authors: Chun-hsiung Hung
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/65622341186095474410

碩士 === 國立中興大學 === 環境工程學系所 === 96 === The anaerobic ammonia oxidation(ANAMMOX) reaction is a minor pathway in the nitrogen cycle. The anaerobic ammonia oxidation bacteria could directly oxidized ammonium and nitrite to nitrogen gas under anoxic conditions by the following equation NH4+ + NO2- → N2 + 2H2O. Anammox reaction, which is different from the traditional nitrification and denitrification reaction, is important for the balance of the nitrogen cycle under lower oxygen concentration environment. Microorganisms which participate in this reaction grow extremely slow. For this reason, using novel 16S rDNA based techniques to determine the phylogenetic identities of the dominant members of the microbial community is necessary. In this research, the microbial community structures of different type anaerobic ammonia oxidation reactors (developed by ITRI) including UASB system、UASB with BioNET cotton system and partial nitrification/Anommox system with BioNET cotton operated under various influent concentrations were studies using PCR-DGGE and FISH techniques. The relationship between the microbial community structures and nitrogen removal efficiency were compared. Experimental results showed that Anammox primer(PLA46 & Amx368-B) could successfully distinguish different Anammox species in all tested systems. Sequences collected from DGGE (denaturing gradient gel electrophoresis) gel have sequence identities ranging from 93-99% comparing to the 16S rDNA sequence in NCBI database. BioNET biological system has a complex microbial community but its Anammox cell count is low. There is a non-Anammox bacteria population which could compete nitrogen source with Anammox bacteria existed in the UASB with BioNET system and resulted a more complex microbial community. Nitrogen removal efficiencies for these two systems maintained at around 80% despite the difference in microorganism composition. Among these three systems, the Partial nitrification/Anammpx with BioNET system seems to have the most complex bacteria structures. Therefore, non-anammox bacteria could significantly compete substrate with Anammox bacteria and results a lower nitrogen removing efficiency (30~70%) in the Partial nitrification/Anammpx with BioNET system. As for the total microbial community analysis, non-Anammox bacterium include ammonia oxidization bacteria、Nitrospira sp., heterotrophic bacteria and unidentified bacterium co-existed with Anammox community in these tested systems. The competition between all these microorganisms significantly affected the denitrification efficiency. Further studies on exploring these particular bacterial interactions are needed.