TABLE 1.

Chemical classes and mechanisms of action of biocides and metabolic inhibitors used to kill or inhibit SRB

Metabolic inhibitor or biocide	Chemical nature and mechanism of action	Classa	Reference(s)	MICb
Metabolic inhibitors
Nitrite	Sulfite analog; inhibitor of dissimilatory sulfite reductase	S	13	5 mM
Molybdate	Sulfate analog; converted to adenosine phosphomolybdate by ATP sulfurylase; hydrolysis of adenosine phosphomolybdate depletes cellular ATP reserves	S	30, 32	3 mM
Biocides
Bronopol	Alcohol; inactivates sulfhydryl group-containing proteins	T	3, 19, 28	4 mM
Formaldehyde	Aldehyde; cross-links amino groups of proteins and nucleic acids	X	4, 5, 19	6 mM
Glutaraldehyde	Aldehyde; cross-links amino and sulfhydryl groups of proteins and nucleic acids	X	3, 5, 19	5 mM
Benzalkonium chloride	Quaternary ammonium cationic surfactant; solubilizes cell membrane and may improve uptake of other antimicrobials	C	3, 27	50 mg/liter
Cocodiaminec	Same as benzalkonium chloride	C	3, 27	0.003% (vol/vol)
THPS	Quaternary phosphonium; mechanism of action unknown; unlikely to work as a surfactant in view of the short side chains	U	9, 10	0.1 mM

^aS, metabolic inhibitor of sulfate reduction; X, cross-linking agent; C, cationic surfactant; T, thiol inactivator; U, unknown.

^bDetermined in this study. The MIC was the minimum concentration that prevented sulfide production by the SRB consortium for 1 month under conditions described in the text.

^cCocodiamine is the trivial name for 1-alkyl (C₆-C₁₈)-1,3 propane diamine acetate.