Hexavalent chromium removal by a novel Serratia proteamaculans isolated from the bank of Sebou River (Morocco)

• Published in: Environmental science and pollution research international Vol. 21; no. 4; pp. 3060 - 3072
• Main Authors: Tahri Joutey, Nezha, Bahafid, Wifak, Sayel, Hanane, Ananou, Samir, El Ghachtouli, Naïma
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.02.2014; Springer Nature B.V
• Subjects: Adsorption; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Bacteria; Biodegradation, Environmental; Bioremediation; Cell surface; Chromate reductase; Chromium; Chromium - chemistry; Chromium - metabolism; DNA methylation; DNA, Bacterial - genetics; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental impact; Environmental Pollutants - metabolism; Enzymes; Filtrate; Freshwater; Heavy metals; Hydrogen-Ion Concentration; Laboratories; Metals; Microorganisms; Molecular Sequence Data; Morocco; Oxidation-Reduction; Phylogenetics; Phylogeny; Research Article; Rivers; RNA, Ribosomal, 16S - genetics; Sequence Analysis, RNA; Serratia - genetics; Serratia - isolation & purification; Serratia - metabolism; Serratia proteamaculans; Soil Microbiology; Studies; Temperature; Temperature tolerance; Toxicity; Waste Water Technology; Water Management; Water pollution; Water Pollution Control; Morocco; Morocco, Sebou R; Hexavalent chromium; Chromium-reducing activity; Bioremediation; Adsorption
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-013-2249-x

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.