title: Hexavalent chromium removal by a novel Serratia proteamaculans isolated from the bank of Sebou River (Morocco).
abstract: The novel Serratia proteamaculans isolated from a chromium-contaminated site was tolerant to a concentration of 500 mg Cr(VI)/l. The optimum pH and temperature for reduction of Cr(VI) by S. proteamaculans were found to be 7.0 and 30 °C, respectively. The Cr(VI) reduction rate decreased with the increase in Cr(VI) concentration from 100 to 400 mg/l, suggesting the enzymatic chromium reduction. Resting and permeabilised cell assays provided the better evidence that chromate reduction in S. proteamaculans is enzymatic. Reduction by cell-free filtrate shows no extracellular chromate-reducing activity, revealing that this activity may be associated to membrane fraction and/or cytosolic fraction. Assays conducted with cytosolic and particulate fraction of S. proteamaculans confirmed the role of membrane-bound proteins in Cr(VI) reduction. Furthermore, chromium reduced by heat-treated cells suggests that membrane-associated chromate reductase activity of S. proteamaculans is preceded by its adsorption on the cell surface.
authors.affiliation: Microbial Biotechnology Laboratory, Faculty of Sciences and Techniques, Sidi Mohamed Ben Abdellah University, Route Immouzer, P. O. Box 2202, Fez, Morocco.
authors.forename: Nezha
authors.initials: N
authors.lastname: Tahri Joutey
authors.forename: Wifak
authors.initials: W
authors.lastname: Bahafid
authors.forename: Hanane
authors.initials: H
authors.lastname: Sayel
authors.forename: Samir
authors.initials: S
authors.lastname: Ananou
authors.forename: Naïma
authors.initials: N
authors.lastname: El Ghachtouli
mesh_terms: D001673:Biodegradation, Environmental; D002857:Chromium / Q000737:chemistry / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics; D004785:Environmental Pollutants / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D009018:Morocco; D010084:Oxidation-Reduction; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D045483:Rivers; D017423:Sequence Analysis, RNA; D012705:Serratia / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D012988:Soil Microbiology; D013696:Temperature
chemical_list: D004269:DNA, Bacterial; D004785:Environmental Pollutants; D012336:RNA, Ribosomal, 16S; D002857:Chromium; C074702:chromium hexavalent ion