title: Cr(VI) resistance and removal by indigenous bacteria isolated from chromium-contaminated soil.
abstract: The removal of toxic Cr(VI) by microorganisms is a promising approach for Cr(VI) pollution remediation. In the present study, four indigenous bacteria, named LY1, LY2, LY6, and LY7, were isolated from Cr(VI)-contaminated soil. Among the four Cr(VI)-resistant isolates, strain LY6 displayed the highest Cr(VI)-removing ability, with 100 mg/l Cr(VI) being completely removed within 144 h. It could effectively remove Cr(VI) over a wide pH range from 5.5 to 9.5, with the optimal pH of 8.5. The amount of Cr(VI) removed increased with initial Cr(VI) concentration. Data from the time-course analysis of Cr(VI) removal by strain LY6 followed first-order kinetics. Based on the 16S rRNA gene sequence, strain LY6 was identified as Pseudochrobactrum asaccharolyticum, a species that had never been reported for Cr(VI) removal before. Transmission electron microscopy and energy dispersive X-ray spectroscopy analysis further confirmed that strain LY6 could accumulate chromium within the cell while conducting Cr(VI) removal. The results suggested that the indigenous bacterial strain LY6 would be a new candidate for potential application in Cr(VI) pollution bioremediation.
authors.affiliation: Institute of Environmental Science and Technology, Zhejiang University, Hangzhou, 310058, Zhejiang, PR China.
authors.forename: Dongyan
authors.initials: D
authors.lastname: Long
authors.forename: Xianjin
authors.initials: X
authors.lastname: Tang
authors.forename: Kuan
authors.initials: K
authors.lastname: Cai
authors.forename: Guangcun
authors.initials: G
authors.lastname: Chen
authors.forename: Chaofeng
authors.initials: C
authors.lastname: Shen
authors.forename: Jiyan
authors.initials: J
authors.lastname: Shi
authors.forename: Linggui
authors.initials: L
authors.lastname: Chen
authors.forename: Yingxu
authors.initials: Y
authors.lastname: Chen
mesh_terms: D042021:Brucellaceae / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002857:Chromium / Q000378:metabolism* / Q000633:toxicity*; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D024881:Drug Resistance, Bacterial; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism* / Q000633:toxicity*; D013052:Spectrometry, X-Ray Emission
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D012989:Soil Pollutants; D002857:Chromium; C074702:chromium hexavalent ion