Inhibiting mild steel corrosion from sulfate-reducing bacteria using antimicrobial-producing biofilms in Three-Mile-Island process water.
Biofilms were used to produce gramicidin S (a cyclic decapeptide) to inhibit corrosion-causing, sulfate-reducing bacteria (SRB). In laboratory studies these biofilms protected mild steel 1010 continuously from corrosion in the aggressive, cooling service water of the AmerGen Three-Mile-Island (TMI) nuclear plant, which was augmented with reference SRB. The growth of both reference SRB (Gram-positive Desulfosporosinus orientis and Gram-negative Desulfovibrio vulgaris) was shown to be inhibited by supernatants of the gramicidin-S-producing bacteria as well as by purified gramicidin S. Electrochemical impedance spectroscopy and mass loss measurements showed that the protective biofilms decreased the corrosion rate of mild steel by 2- to 10-fold when challenged with the natural SRB of the TMI process water supplemented with D. orientis or D. vulgaris. The relative corrosion inhibition efficiency was 50-90% in continuous reactors, compared to a biofilm control which did not produce the antimicrobial gramicidin S. Scanning electron microscope and reactor images also revealed that SRB attack was thwarted by protective biofilms that secrete gramicidin S. A consortium of beneficial bacteria (GGPST consortium, producing gramicidin S and other antimicrobials) also protected the mild steel.
Zuo
R
R
Departments of Chemical Engineering & Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269-3222, USA.
Ornek
D
D
Syrett
B C
BC
Green
R M
RM
Hsu
C-H
CH
Mansfeld
F B
FB
Wood
T K
TK
D000900:Anti-Bacterial Agents / Q000096:biosynthesis* / Q000494:pharmacology; D000898:Antibiosis; D001419:Bacteria / Q000254:growth & development* / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism / Q000494:pharmacology; D001430:Bacteriocins; D018441:Biofilms / Q000254:growth & development*; D001709:Biotechnology / Q000379:methods; D003343:Corrosion; D003901:Desulfovibrio / Q000187:drug effects / Q000254:growth & development; D006096:Gramicidin / Q000096:biosynthesis / Q000494:pharmacology; D007218:Industrial Microbiology / Q000379:methods; D010084:Oxidation-Reduction; D010455:Peptides / Q000378:metabolism / Q000494:pharmacology; D010459:Peptococcaceae / Q000187:drug effects / Q000254:growth & development; D011113:Polymyxins / Q000096:biosynthesis / Q000494:pharmacology; D013232:Steel / Q000737:chemistry; D016999:Sulfur-Reducing Bacteria / Q000187:drug effects / Q000254:growth & development*; D014440:Tyrocidine / Q000096:biosynthesis / Q000494:pharmacology; D014871:Water Microbiology
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D001430:Bacteriocins; D010455:Peptides; D011113:Polymyxins; D014440:Tyrocidine; D013232:Steel; D006096:Gramicidin; C002836:subtilin