Jason Flowers Metabolic Characterization of Candidatus Accumulibacter Phosphatis Using Metaproteomic Analysis

In many freshwater bodies, phosphorus is a limiting nutrient for bacterial growth. To prevent eutrophication,... » More

In many freshwater bodies, phosphorus is a limiting nutrient for bacterial growth. To prevent eutrophication, enhanced biological phosphorus removal (EBPR) of waste water has been successfully applied at sewage plants for the past thirty years. Previous researchers could only speculate about the biochemical pathways involved in EBPR principally because the organisms responsible for EBPR cannot be isolated in pure culture. Using metagenomic data recently obtained from a Candidatus Accumulibacter phosphatis (Accumulibacter) enriched bioreactor, we have investigated the metabolism of EBPR through metaproteomic analysis. A total of six protein samples were collected for metaproteomic analysis. Proteins were extracted and either digested with trypsin in a 1D SDS PAGE and run on a LC-MS/MS or digested in solution with trypsin and run on a 2D LC-MS/MS for protein identification. For all samples, peptide MS data was analyzed using Sequest to construct the original protein sequence by comparison to the previously sequenced metagenome. A total of 964 proteins were matched across all samples. 223 proteins were observed in at least two samples with only 80 identified as originating from Accumulibacter. We were able to reconstruct the carbon metabolism for Accumulibacter including nearly all proteins for glycolysis, TCA cycle, and the glyoxylate bypass. Additionally, we observed EBPR relevant proteins including polyphosphate kinase and PHA synthase. The overall results confirm the expression of several pathways required for EBPR metabolism, but more work is required to capture the complete proteome that will improve our understanding of the process. « Hide