Lokesh Padhye - Biotransformation of nitrosamines and precursor secondary amines under methanogenic conditions

Version 1

      Publication Details (including relevant citation   information):

    Tezel U, Padhye LP, Huang CH, Pavlostathis SG. Environ Sci Technol. 2011 Oct 1;45(19):8290-7.


        The biotransformation potential of six nitrosamines and their   precursor secondary amines by a mixed methanogenic culture was   investigated. Among the six nitrosamines tested,    N-nitrosodimethylamine   (NDMA),   N-nitrosomethylethylamine   (NMEA), and   N-nitrosopyrrolidine   (NPYR) were almost completely degraded but only when degradable   electron donors were available. On the contrary,    N-nitrosodiethylamine   (NDEA),   N-nitrosodipropylamine   (NDPA), and   N-nitrosodibutylamine   (NDBA) were not degraded. Three precursor secondary amines,   corresponding to the three biodegradable nitrosamines, were also   completely utilized even with very low levels of available   electron donors. The secondary amine precursors of the three,   nonbiodegradable nitrosamines were also recalcitrant. A bioassay   conducted to elucidate the biotransformation pathway of NDMA in   the mixed methanogenic culture using H2    as the electron donor showed that NDMA was utilized as an   electron acceptor and transformed to dimethylamine (DMA), which   in turn was degraded to ammonia and methane. The   H2    threshold concentration for NDMA bioreduction ranged between   0.0017 and 0.031 atm. Such a high H2    threshold concentration suggests that in mixed methanogenic   cultures, NDMA reducers are weak competitors to other,   H2-consuming   microbial species, such as homoacetogens and methanogens. Thus,   complete removal of nitrosamines in anaerobic digestion systems,   where the H2    partial pressure is typically below 10–4    atm, is difficult to achieve.

      Address (URL): http://pubs.acs.org/doi/abs/10.1021/es2005557?prevSearch=%255BContrib%253A%2BPad hye%252C%2BLokesh%2BP.%255D&searchHistoryKey=