PCR- RFLP based bacterial diversity analysis of a municipal sewage treatment plant

Bacterial diversity of sewage soil is an essential study to discover novel bacterial species involved in biodegradation. Restriction Fragment Length Polymorphism is one of the most useful molecular technique for diversity analysis in terms of cost effectiveness and reliability. The present study focuses on bacterial diversity of municipal sewage treatment plant in Chennai, Tamil Nadu, India through metagenomic approach. A 16S r DNA clone library was constructed from metagenomic DNA of sewage soil. 200 clones from the library were subjected to colony PCR and RFLP analysis. Upon RFLP analysis, 16 different Operational Taxonomic Units (OTU's) were obtained and a single clone from each OTU was subjected to sequencing. Phylogenetic analysis of sequences revealed the presence of five different groups of bacteria namely Proteobacteria (56%), Actinobacteria (7%), Firmicutes (5%), Bacteroidetes (17%) and Plancomycetes (7%). Three novel and uncultured groups of bacteria (8%) were also discovered. Most of the organisms identified through this study were reported to be efficient degraders of hydrocarbons, aromatic compounds and heavy metals, thereby promoting biodegradation of polluted environment.