Genomic, Proteomic, and Metabolite Characterization of Gemfibrozil-Degrading Organism <i>Bacillus</i> 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. <i>Bacillus</i> sp. GeD10, a gemfibrozil-degrader, was previously isolated from activated sludge. It is the first identified bacterium capable of degrading gemfibrozil. Gemfibrozil degradation by <i>Bacillus</i> sp. GeD10 was here studied through genome sequencing, quantitative proteomics and metabolite analysis. From the bacterial proteome of <i>Bacillus</i> sp. GeD10 1974 proteins were quantified, of which 284 proteins were found to be overabundant by more than 2-fold (FDR corrected <i>p</i>-value ≤0.032, fold change (log<sub>2</sub>) ≥ 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 <i>Bacillus</i> 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.