Community diversity and abundance of biofilms from a full-scale drinking water distribution system in Shanghai were characterized by denaturing gradient gel electrophoresis (DGGE) analysis of 16S rRNA sequences and heterotrophic plate count (HPC), respectively. Bacteria affiliated to the Beta- and Gamma-Proteobacteria were dominating in both in-situ and HPC-culturable bacterial communities. Other bacteria present included members of Alphaproteobacteria, Bacteroides, Actinobacteria, Nitrospirae and Firmicutes. Acidovorax, Ralstonia and Acinetobacter were common species in biofilms. Klebsiella pneumoniae and Enterobacter sp. were detected in the local distribution system. Dissolved organic carbon (DOC), residual disinfectant and temperature were the most important factors influencing both bacterial abundance and composition. HPC for biofilm sample was not correlated with its community diversity.
Keywords: biofilm, community diversity, heterotrophic plate count, PCR-DGGE, water distribution system