Microbial degradation of Benzyldimethyl Hexadecylammonium Chloride (BDHAC) used in oilfield chemical formulations

Following enrichment in its presence, four strains of bacteria, isolated from marine sediments, were shown to degrade the quaternary ammonium surfactant Benzyldimethyl Hexadecylammonium Chloride (BDHAC) in a minimal salts medium. The bacteria were identified by 16S rDNA sequencing, were shown to belong to several genera and were identified as Bacillus niabensis, Bacillus subtilis, Thalassospira sp, and Sporosarcina sp. Initial investigations have shown that the bacteria are capable of degrading BDHAC when it is present at concentrations in the range 2-4 mg/ml. In media containing BDHAC, up to 90% was degraded within 7 days, but this supported only limited growth of the bacteria. Preliminary analysis of samples after degradation experiment by ESI-MS/MS produced a peak with a parent-daughter ion transition of 136.0-91.0, corresponding to N, N-dimethylbenzylamine. The presence of this potential metabolite suggests the cleavage of the C alkyl-N bond as a step in BDHAC catabolism. Copyright 2009, Society of Petroleum Engineers.