Assessment Of 2,2-Dibromo-3-Nitrilopropionamide Biocide Enhanced By D-Tyrosine Against Zinc Corrosion By A Sulfate Reducing Bacterium

The biocorrosion of pure zinc by sulfate reducing bacterium (SRB) Desulfovibrio vulgaris was found to be very severe (2.3 +/- 0.1 mm/y) after 7 d incubation in 100 mL of ATCC 1249 medium at 37 degrees C in 125 mL anaerobic vials. D-tyrosine was evaluated as a biocide enhancer for the 2,2-dibromo-3-nitrilopropionamide (DBNPA) biocide mitigation of microbiologically influenced corrosion (MIC). The 100 ppm (w/w) DBNPA alone treatment was found to reduce the SRB sessile cell count by 2-log, zinc weight loss by 48%, and corrosion pit depth by 86%. This biocide treatment was enhanced by its combination with 1 ppm D-tyrosine, which achieved 4-log sessile cell reduction, 70% zinc weight loss reduction, and 92% pit depth reduction compared with the untreated control. Headspace H2S concentrations confirmed that better biocide treatment led to less biogenic H2S. Electrochemical corrosion data supported weight loss and pit depth data.