Bacterial Diversity in Sludge

Bacteria is one of two domains of prokaryotic organisms and they are found in a plethora of diverse habitats from mountains, to ocean bottoms, to waste water. It is reported that about 99% of environmental bacteria are uncultivated. The study of bacterial diversity is crucial to understand their ecological role. Molecular techniques (PCR, cloning, and sequencing) and metagenomics studies are used to reveal the diversity of bacteria in various habitats. The 16S ribosomal RNA subunit is a universally conserved gene in prokaryotes and about 1500 bp in length. 16S rRNA was used in this study due to its high information content and its use in sequence comparison. 

The goal of this project is to study the diversity of uncultivated bacteria found in wastewater. Our methods consisted of cloning PCR-amplified 16S rDNA genes, and analyzing sequences using bioinformatics. Our results showed that a variety of bacterial species exist our wastewater samples, as expected. However, a number of those sequences suggest we discovered new bacterial types. In addition our results have shown that 92% of the clones sequenced belonged to the proteobacteria phylum. Within the proteobacteria, the subgroup beta-proteobacteria was the most abundant (66%). Other abundant phyla include actinobactera (3%), bacteroidetes, firmicutes (1.5%), acidiobacteria, spirochaetes, and planctomycetes (0.7%).  These results are comparable to previous data from wastewater. Our findings aid in the classification and characterization of the microbial diversity in those environments. It is predicted that deeper sequencing could identify more novel species of uncultivated bacteria.