Degradation of benzyldimethyl hexadecylammonium chloride by Bacillus niabensis and Thalassospira sp. isolated from marine sediments

Following enrichment in its presence, two 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 identified by 16S ribosomal deoxyribonucleic acid sequencing were shown to belong to several genera and determined to be Bacillus niabensis and Thalassospira sp. Initial investigations demonstrated that the bacteria were capable of degrading BDHAC when it was present at concentrations in the range 2–4 mg mL^?1. In media containing BDHAC, up to 90% was degraded within 7 days, but limited growth of the strain was observed at 2 and 4 mg mL^?1 BDHAC. Preliminary analysis of samples after degradation experiment by electrospray ionization mass spectrometry/mass spectrometry produced a peak with a parent–daughter ion transition of 136 → 91, 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.