Isolation of bacterial strains in wastewater sludge capable of degradation of Sertraline, Venlafaxine and Triclocarban

Jonathan Fox, The College of Wooster


Pharmaceuticals and other chemical compounds used in many personal care products are becoming environmental problems by effecting aquatic life. Sertraline and venlafaxine are highly prescribed pharmaceuticals that are passing through the wastewater treatment plant and polluting our environment. Sertraline and venlafaxine are selective serotonin reuptake inhibitors used to control depression in many people while triclocarban is an antimicrobial agent found in many personal care products. There is little known about the degradation of sertraline and venlafaxine in the environment and recent studies have suggested bacteria from the Wooster wastewater treatment plant possess the ability to degrade these chemicals. The goal of this project was to isolate and identify the bacterial strains capable of degrading sertraline, venlafaxine, and triclocarban. Using wastewater sludge and minimal media with each chemical compound as the only carbon source, colonies of bacteria capable of degradation were examined. Multiple microcosms of wastewater treatment plant sludge showed the ability to degrade venlafaxine (2 days) and sertraline (10 days). The microcosms were able to completely degrade the chemicals, however no single colonies could be propagated long enough from the microcosms to ensure pure bacterial strains capable of degradation. Eventually, 2 distinct bacterial strains were isolated from different microcosm but the strains would not grow after movement from minimal media to carbon rich media and back to minimal media. Isolating the bacteria into single colonies may be a reason for the absence of growth. Research has indicated some bacteria utilize the byproducts from other bacteria and need to be found together to survive and degrade certain chemicals. This may explain why the single colonies could not survive in minimal media. Another possible explanation for the difficulty in isolating bacteria is the difference in microcosms. The microcosms were taken during the summer, fall, and winter months so the bacteria present may be different from one microcosm to the next. Further studies are necessary to identify if the bacteria are in a synergistic relationship with other bacterial strains or if the different microcosms have different microbial species.  


© Copyright 2012 Jonathan Fox