Application of rRNA-targeted oligonucleotide probes in the analysis of microbial communities in activated sludge

Wastewater treatment by activated sludge is one of the most important biotechnological processes and has been used for more than 80 years. However, the information on correlations between the microbial community structure and function of activated sludge is less provided. Due to intricate interactions within the microbial community, it is important to detect the prominent population and describe microbial community structure in the wastewater treatment process. Conventional cultivation methods often result in pronounced population shifts in the community structure and lead to a failure to detect dominant bacterial community memmbers. Recently, rRNA targeted oligonucleotide probes were introduced as a new powerful tool in situ monitoring microbial ecology in activated sludge and have made revolutionary progresses. Based on it, microbial ecologists can for the first time determine the true composition of microbial communities. This review introduces the identification of it in structure and function of microbial communities in phosphate removing activated sludge, nitrifying activated sludge, bulking sludge and foaming activated sludge, summarizes most of probes which have been developed and used, analyzes the advantages and disvantages of it.