Mitigation of the Desulfovibrio vulgaris biofilm using alkyldimethylbenzylammonium chloride enhanced by d-amino acids

d-tyrosine and d-methionine that are naturally occurring chemicals were investigated as enhancers for alkyldimethylbenzylammonium chloride (ADBAC) against the Desulfovibrio vulgaris biofilm on C1018 coupons surfaces in ATCC 1249 culture medium. The 7-day biofilm prevention results showed that the d-amino acids alone had only limited effects on SRB sessile cell counts. Ten ppm (w/w) ADBAC alone achieved a 1-log reduction in SRB sessile cell count compared with the untreated control. The combination of 1 ppm d-tyrosine + 10 ppm ADBAC achieved 3 extra log reduction and 50 ppm d-methionine + 10 ppm ADBAC achieved 2 extra log reduction compared with the 10 ppm ADBAC alone treatment. In the biofilm removal test, both combinations exhibited 2 extra log reduction compared with the 10 ppm ADBAC alone treatment. These results were supported by scanning electron microscope images and confocal laser scanning microscope images of the biofilms.