title: Isolation of a sulfide-producing bacterial consortium from cooling-tower water: Evaluation of corrosive effects on galvanized steel.
abstract: Sulfidogenic Clostridia and sulfate reducing bacteria (SRB) often cohabit in nature. The presence of these microorganisms can cause microbially influenced corrosion (MIC) of materials in different ways. To investigate this aspect, bacteria were isolated from cooling tower water and used in corrosion tests of galvanized steel. The identity of the isolates was determined by comparative sequence analysis of PCR-amplified 16S rDNA gene fragments, separated by denaturing gradient gel electrophoresis (DGGE). This analysis showed that, in spite of the isolation process, colonies were not pure and consisted of a mixture of bacteria affiliated with Desulfosporosinus meridiei and Clostridium sp. To evaluate the corrosive effect, galvanized steel coupons were incubated with a mixed culture for 4, 8, 24, 72, 96, 168, 360 and 744 h, along with a control set in sterile culture medium only. The corrosion rate was determined by weight loss, and biofilm formation and corroded surfaces were observed by scanning electron microscopy (SEM). Although the sulfide-producing bacterial consortium led to a slight increase in the corrosion of galvanized steel coupons, when compared to the previous studies it can be said that Clostridium sp. can reduce the corrosive effect of the Desulfosporosinus sp. strain.
authors.affiliation: Department of Biology, Istanbul University, 34134, Vezneciler, Istanbul, Turkey. Electronic address: esungur@istanbul.edu.tr.
authors.forename: Esra
authors.initials: E
authors.lastname: Ilhan-Sungur
authors.affiliation: Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.
authors.forename: Derya
authors.initials: D
authors.lastname: Ozuolmez
authors.affiliation: Department of Biology, Istanbul University, 34134, Vezneciler, Istanbul, Turkey.
authors.forename: Ayşın
authors.initials: A
authors.lastname: Çotuk
authors.affiliation: Metallurgical and Materials Engineering Department, Yıldız Technical University, Istanbul, Turkey.
authors.forename: Nurhan
authors.initials: N
authors.lastname: Cansever
authors.affiliation: Microbial Systems Ecology, Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Gerard
authors.initials: G
authors.lastname: Muyzer
mesh_terms: D000389:Air Conditioning; D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D018441:Biofilms / Q000187:drug effects*; D002241:Carbohydrates / Q000032:analysis; D003013:Clostridium / Q000235:genetics / Q000378:metabolism; D003343:Corrosion; D004269:DNA, Bacterial / Q000737:chemistry; D004275:DNA, Ribosomal / Q000737:chemistry; D058645:Denaturing Gradient Gel Electrophoresis; D003901:Desulfovibrio / Q000235:genetics / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D010459:Peptococcaceae / Q000235:genetics / Q000378:metabolism; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D016415:Sequence Alignment; D013232:Steel / Q000737:chemistry*; D013440:Sulfides / Q000378:metabolism*; D014871:Water Microbiology; D015032:Zinc / Q000032:analysis
chemical_list: D002241:Carbohydrates; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D013440:Sulfides; D013232:Steel; D015032:Zinc
keywords: Bacterial consortium; Clostridium sp.; Cooling tower; Desulfosporosinus meridiei; Galvanized steel; Microbiologically influenced corrosion