title: Hexavalent chromium reduction by Acinetobacter haemolyticus isolated from heavy-metal contaminated wastewater.
abstract: Possible application of a locally isolated environmental isolate, Acinetobacter haemolyticus to remediate Cr(VI) contamination in water system was demonstrated. Cr(VI) reduction by A. haemolyticus seems to favour the lower concentrations (10-30 mg/L). However, incomplete Cr(VI) reduction occurred at 70-100 mg/L Cr(VI). Initial specific reduction rate increased with Cr(VI) concentrations. Cr(VI) reduction was not affected by 1 or 10 mM sodium azide (metabolic inhibitor), 10 mM of PO(4)3-, SO4(2-), SO(3)2-, NO3- or 30 mg/L of Pb(II), Zn(II), Cd(II) ions. However, heat treatment caused significant dropped in Cr(VI) reduction to less than 20% only. A. haemolyticus cells loses its shape and size after exposure to 10 and 50 mg Cr(VI)/L as revealed from TEM examination. The presence of electron-dense particles in the cytoplasmic region of the bacteria suggested deposition of chromium in the cells.
authors.affiliation: Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia.
authors.forename: Zainul Akmar
authors.initials: ZA
authors.lastname: Zakaria
authors.forename: Zainoha
authors.initials: Z
authors.lastname: Zakaria
authors.forename: Salmijah
authors.initials: S
authors.lastname: Surif
authors.forename: Wan Azlina
authors.initials: WA
authors.lastname: Ahmad
mesh_terms: D000150:Acinetobacter / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D000838:Anions / Q000494:pharmacology; D002244:Carbon / Q000494:pharmacology; D002857:Chromium / Q000378:metabolism*; D006358:Hot Temperature; D007220:Industrial Waste; D019216:Metals, Heavy / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D010084:Oxidation-Reduction; D019810:Sodium Azide / Q000494:pharmacology; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000378:metabolism*; D018508:Water Purification / Q000379:methods
chemical_list: D000838:Anions; D007220:Industrial Waste; D019216:Metals, Heavy; D014874:Water Pollutants, Chemical; D002857:Chromium; C074702:chromium hexavalent ion; D002244:Carbon; D019810:Sodium Azide