Genomic, Proteomic, and Metabolite Characterization of Gemfibrozil-Degrading Organism Bacillus sp. GeD10

Gemfibrozil is a widely used hypolipidemic and triglyceride lowering drug. Excess of the drug is excreted and discharged into the environment primarily via wastewater treatment plant effluents. Bacillus sp. GeD10, a gemfibrozil-degrader, was previously isolated from activated sludge. It is the first identified bacterium capable of degrading gemfibrozil. Gemfibrozil degradation by Bacillus sp. GeD10 was here studied through genome sequencing, quantitative proteomics and metabolite analysis. From the bacterial proteome of Bacillus sp. GeD10 1974 proteins were quantified, of which 284 proteins were found to be overabundant by more than 2-fold (FDR corrected p-value ≤0.032, fold change (log2) ≥ 1) in response to gemfibrozil exposure. Metabolomic analysis identified two hydroxylated intermediates as well as a glucuronidated hydroxyl-metabolite of gemfibrozil. Overall, gemfibrozil exposure in Bacillus sp. GeD10 increased the abundance of several enzymes potentially involved in gemfibrozil degradation as well as resulted in the production of several gemfibrozil metabolites. The potential catabolic pathway/modification included ring-hydroxylation preparing the substrate for subsequent ring cleavage by a meta-cleaving enzyme. The identified genes may allow for monitoring of potential gemfibrozil-degrading organisms in situ and increase the understanding of microbial processing of trace level contaminants. This study represents the first omics study on a gemfibrozil-degrading bacterium.