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Biodegradability is an important consideration in the design of novel chemicals. At the end of their function, chemicals should break down into harmless degradation products to avoid toxic effects as a result of environmental persistence. To test the biodegradability potential of novel chemicals, a protocol designed by the Organisation for Economic and Cooperative Development (OECD) is used. This protocol states that in a mixture of the chemical of interest, a microbial inoculate, and mineral media, 70% of the chemical must degrade within a 10-day window of a 28-day experiment in order to be considered readily biodegradable. The protocol states that the microbial inoculate can be obtained from one of several possible locations, such as a Wastewater Treatment Plant (WWTP), at any time point. Because of this, the microbial community is taken as a constant, when instead it has shown to be variable. In multiple OECD-driven experiments using the same chemical of interest, different biodegradation results were recorded. This is problematic, as the data collected may not be useful and will not provide the correct information concerning the fate of the chemical once it enters the environment. In this experiment, we tested the biodegradability of novel green chemicals, Ionic Liquids (ILs). Varying biodegradation from previous experiments make them an ideal candidate for this experiment. We predict that the microbial community involved in the biodegradation process varies by the location and the time point during the year it is collected. In this experiment, we collected microbial inoculate from two different sampling sites at three time points in a year, for use in an experiment prepared in accordance with the OECD protocol. We quantified biodegradation by measuring the absorbance of the pyridinium or imidalizolium ring (depending on the IL used), as well as the total organic carbon concentrations (June experiment only). Additionally, we performed Terminal Restriction Fragment Length Polymorphism (TRFL-P) analysis to provide insight into the microbial community present. Our results suggest that microbial community structure varies between locations and across different time points in a year, and that this variation affects the biodegradation of ILs.
Aiello, Steven, "The Effect of Regional and Seasonal Variability in Wastewater Microbial Community Structure on the Biodegradability of Room Temperature Ionic Liquids" (2014). Honors Theses. 2402.
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