title: Monitoring sulfide-oxidizing biofilm activity on cement surfaces using non-invasive self-referencing microsensors.
abstract: Microbially influenced corrosion (MIC) in concrete results in significant cost for infrastructure maintenance. Prior studies have employed molecular techniques to identify microbial community species in corroded concrete, but failed to explore bacterial activity and functionality during deterioration. In this study, biofilms of different sulfur-oxidizing bacteria compositions were developed on the surface of cement paste samples to simulate the natural ecological succession of microbial communities during MIC processes. Noninvasive, self-referencing (SR) microsensors were used to quantify real time changes of oxygen, hydrogen ion and calcium ion flux for the biofilm to provide more information about bacterial behavior during deterioration. Results showed higher transport rates in oxygen consumption, and hydrogen ion at 4 weeks than 2 weeks, indicating increased bacterial activity over time. Samples with five species biofilm had the highest hydrogen ion and calcium ion transport rates, confirming attribution of acidophilic sulfur-oxidizing microorganisms (ASOM). Differences in transport rates between three species samples and two species samples confirmed the diversity between Thiomonas intermedia and Starkeya novella. The limitations of SR sensors in corrosion application could be improved in future studies when combined with molecular techniques to identify the roles of major bacterial species in the deterioration process.
authors.affiliation: Zachry Department of Civil Engineering, Texas A&M University, 3136 TAMU, College Station, TX 77843-3136, USA. Electronic address: liqiucheng@tamu.edu.
authors.forename: Liqiu
authors.initials: L
authors.lastname: Cheng
authors.affiliation: Lyles School of Civil Engineering, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47907-2051, USA.
authors.forename: Mitch W
authors.initials: MW
authors.lastname: House
authors.affiliation: Lyles School of Civil Engineering, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47907-2051, USA; Bindley Bioscience Center, Physiological Sensing Facility, Discovery Park, Purdue University, 1203 W. State Street, West Lafayette, IN 47907-2057, USA.
authors.forename: W Jason
authors.initials: WJ
authors.lastname: Weiss
authors.affiliation: Zachry Department of Civil Engineering, Texas A&M University, 3136 TAMU, College Station, TX 77843-3136, USA.
authors.forename: M Katherine
authors.initials: MK
authors.lastname: Banks
mesh_terms: D001419:Bacteria / Q000254:growth & development* / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development*; D015374:Biosensing Techniques; D002118:Calcium / Q000378:metabolism; D003252:Construction Materials / Q000382:microbiology*; D003343:Corrosion; D044222:Halothiobacillus; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D013440:Sulfides / Q000737:chemistry*; D014871:Water Microbiology
chemical_list: D013440:Sulfides; D010100:Oxygen; D002118:Calcium
keywords: Biofilm; Microbially influenced corrosion; Self-referring microsensors; Sulfide-oxidizing bacteria