title: Adhesion of Escherichia coli onto quartz, hematite and corundum: extended DLVO theory and flotation behavior.
abstract: The adhesion of Escherichia coli onto quartz, hematite and corundum was experimentally investigated. A strain of E. coli was used that had the genes for expressing protein for silica precipitation. The maximum cell adhesion was observed at pH <4.3 for quartz and at pH 4.5-8.5 for corundum. For hematite, cell adhesion remained low at all pH values. The microbe-mineral adhesion was assessed by the extended DLVO theory approach. The essential parameters for calculation of microbe-mineral interaction energy (Hamaker constants and acid-base components) were experimentally determined. The extended DLVO approach could be used to explain the results of the adhesion experiments. The effect of E. coli on the floatability of three oxide minerals was determined and the results showed that E. coli can act as a selective collector for quartz at acidic pH values, with 90% of the quartz floated at 1.5 x 10(9)cells/ml. However, only 9% hematite and 30% corundum could be floated under similar conditions. By using E. coli and no reagents, it was possible to separate quartz from a hematite-quartz mixture with Newton's efficiency of 0.70. Removal of quartz from the corundum mixture was achieved by E. coli with Newton's efficiency of 0.62.
authors: Department of Earth Resources Engineering, Faculty of Engineering, Kyushu University, 744 Motooka, Nishiku, Fukuoka 819-0395, Japan. mohsen105@hotmail.com
authors: Mohsen
authors: M
authors: Farahat
authors: Tsuyoshi
authors: T
authors: Hirajima
authors: Keiko
authors: K
authors: Sasaki
authors: Katsumi
authors: K
authors: Doi
mesh_terms: D000143:Acids; D000327:Adsorption; D000537:Aluminum Oxide / Q000378:metabolism*; D001422:Bacterial Adhesion; D004926:Escherichia coli / Q000166:cytology* / Q000502:physiology*; D005290:Ferric Compounds / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008903:Minerals / Q000737:chemistry; D008954:Models, Biological; D011791:Quartz / Q000378:metabolism*; D055672:Static Electricity; D013816:Thermodynamics; D013997:Time Factors
chemical_list: D000143:Acids; D005290:Ferric Compounds; D008903:Minerals; D011791:Quartz; C000499:ferric oxide; D000537:Aluminum Oxide