title: Flocculation behaviour of hematite-kaolinite suspensions in presence of extracellular bacterial proteins and polysaccharides.
abstract: Cells of Bacillus subtilis exhibited higher affinity towards hematite than to kaolinite. Bacterial cells were grown and adapted in the presence of hematite and kaolinite. Higher amounts of mineral-specific proteinaceous compounds were secreted in the presence of kaolinite while hematite-grown cells produced higher amounts of exopolysaccharides. Extracellular proteins (EP) exhibited higher adsorption density on kaolinite which was rendered more hydrophobic. Hematite surfaces were rendered more hydrophilic due to increased adsorption of extracellular polysaccharides (ECP). Significant surface chemical changes were produced due to interaction between minerals and extracellular proteins and polysaccharides. Iron oxides such as hematite could be effectively removed from kaolinite clays using selective bioflocculation of hematite after interaction with EP and ECP extracted from mineral-grown cells.
authors.affiliation: Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, India. Electronic address: spoornimakrishnan@gmail.com.
authors.forename: S
authors.initials: S
authors.lastname: Poorni
authors.affiliation: Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, India. Electronic address: kan@materials.iisc.ernet.in.
authors.forename: K A
authors.initials: KA
authors.lastname: Natarajan
mesh_terms: D000327:Adsorption; D001412:Bacillus subtilis / Q000187:drug effects / Q000254:growth & development; D001426:Bacterial Proteins / Q000737:chemistry*; D005110:Extracellular Space / Q000737:chemistry*; D005290:Ferric Compounds / Q000494:pharmacology*; D005427:Flocculation / Q000187:drug effects; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D007616:Kaolin / Q000494:pharmacology*; D007700:Kinetics; D011134:Polysaccharides / Q000737:chemistry*; D055672:Static Electricity; D013535:Suspensions
chemical_list: D001426:Bacterial Proteins; D005290:Ferric Compounds; D011134:Polysaccharides; D013535:Suspensions; C000499:ferric oxide; D007616:Kaolin
keywords: Bioflocculation; Extracellular proteins; Hematite; Kaolinite; Polysaccharides