Evaluation of Beta Blocker Biotransformation by Mixed Culture Communities Under Nitrifying Conditions

摘要

Water resource recovery facilities (WRRFs) may provide a pathway for pharmaceutically active compounds (PhACs) to enter the environment, many of which may present risk to ecosystems. This motivates exploration into PhAC removal mechanisms within various treatment processes. Ammonia oxidizing bacteria (AOB) co-metabolically biotransform PhACs. Cometabolism involves the transformation of the PhAC as a non-growth substrate in the obligatory presence of the primary energy or growth substrate, ammonium. Biotransformation rates of beta blocker PhACs atenolol, metoprolol, and sotalol were evaluated to determine the relative contribution of AOB and heterotrophs within mixed culture communities. The experimental design assessed the biotransformation of the individual PhACs with mixed cultures from two WRRFs with differing operational conditions. Analysis of the rates showed that AOB degrade atenolol and metoprolol in WWRFs at rates that are disproportionately greater than the contribution of heterotrophs. The results suggest that select process design conditions may promote improved PhAC biotransformation efficiencies.