title: Binding of harvested bacterial exopolymers to the surface of calcite.
abstract: Biologically produced exopolysaccharides (EPS) affect calcite dissolution and precipitation. In this study, natural alkaliphilic microbial isolates were collected from biofilms on historic limestone. The isolates were screened for their ability to produce significant quantities of EPS in cultures. The most productive isolates were identified by 16S rRNA sequence analysis as a close relative of Bacillus cereus. EPS with different chemical structures were harvested from the isolates. Isothermal titration calorimetry (ITC) was used to quantify the thermodynamics of binding by the harvested EPS to calcite. The binding was described by a Langmuir adsorption isotherm. Characterization of the EPS showed that binding strength to calcite depended on the chemical nature of the polymer.
authors.affiliation: Harvard University, Division of Engineering and Applied Sciences, Cambridge, Massachusetts 02138, USA. tperry@deas.harvard.edu
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Perry
authors.forename: Vanja
authors.initials: V
authors.lastname: Klepac-Ceraj
authors.forename: Xiang V
authors.initials: XV
authors.lastname: Zhang
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: McNamara
authors.forename: Martin F
authors.initials: MF
authors.lastname: Polz
authors.forename: Scot T
authors.initials: ST
authors.lastname: Martin
authors.forename: Neal
authors.initials: N
authors.lastname: Berke
authors.forename: Ralph
authors.initials: R
authors.lastname: Mitchell
mesh_terms: D001409:Bacillus cereus / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D002119:Calcium Carbonate / Q000378:metabolism*; D002151:Calorimetry; D004783:Environmental Microbiology; D019015:Geologic Sediments / Q000382:microbiology; D008969:Molecular Sequence Data; D011135:Polysaccharides, Bacterial / Q000302:isolation & purification / Q000378:metabolism*; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012988:Soil Microbiology; D013045:Species Specificity
chemical_list: D011135:Polysaccharides, Bacterial; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D002119:Calcium Carbonate