Evaluation of Cr(VI) reduction mechanism and removal by Cellulosimicrobium funkei strain AR8, a novel haloalkaliphilic bacterium.
The present study, a novel haloalkaliphilic Cr(VI) tolerant bacterial strain, Cellulosimicrobium funkei AR8, was isolated and characterized for its high Cr(VI) reduction. In batch experiments, Cr(VI) reduction was evaluated under different parametric conditions which include different pH (5-9), temperature (25-45°C), NaCl (0-3%) and Cr(VI) concentrations (100-250μg/ml). Variations in the cell surface functional groups and morphology of the bacterial cells after Cr(VI) reduction were characterized by FT-IR and SEM-EDX. FT-IR analysis revealed that cell surface functional groups such as alkanes, amide and amines are involved in chromium biosorption and SEM-EDX results showed that biosorption and immobilization of chromium species on the cell surface. Bioconversion of Cr(VI) into Cr(III) by strain AR8 was confirmed by XRD and Raman spectroscopy analysis. Intracellular localization of reduced product (Cr(III)) was visualized by TEM analysis. Various instrumentation analysis verified that Cr(VI) removal mechanism of C. funkei AR8 strain was achieved by both extra and intracellular reducing machinery. Toxicity study revealed that the bacterially reduced product exerted less toxic effects on phenotypic, survival (91.31%), hatching (84.04%) and heart function (115±1.03 beats/min) of zebrafish (Danio rerio) embryos. Higher Cr(VI) reducing ability of the strain under haloalkaliphilic condition suggests the C. funkei AR8 as a novel and efficient strain for remediating Cr(VI) contaminated industrial effluents with high salinity and alkalinity.
Plant and Microbial Biotechnology Laboratory, Department of Biotechnology, School of Biosciences, Periyar University, Salem, 636 011, Tamil Nadu, India.
Chinnannan
C
Karthik
Plant and Microbial Biotechnology Laboratory, Department of Biotechnology, School of Biosciences, Periyar University, Salem, 636 011, Tamil Nadu, India.
Selvaraj
S
Barathi
Department of Environmental Biotechnology, School of Environmental Sciences, Bharathidasan University, Tamil Nadu, India; Deparment of Environmental Engineering, Daegu University, Gyeongbuk 38453, Republic of Korea.
Arivalagan
A
Pugazhendhi
Department of Environmental Biotechnology, School of Environmental Sciences, Bharathidasan University, Tamil Nadu, India.
Vijayan Sri
VS
Ramkumar
Faculty of Environment and Labour Safety, Ton Duc Thang University, No.19 Nguyen Huu Tho Street, Tan Phong Ward, District 7, Ho Chi Minh City, Viet Nam.
Ngoc Bao Dung
NBD
Thi
Plant and Microbial Biotechnology Laboratory, Department of Biotechnology, School of Biosciences, Periyar University, Salem, 636 011, Tamil Nadu, India. Electronic address: iarulselvibiotech@gmail.com.
Padikasan Indra
PI
Arulselvi
D039903:Actinobacteria / Q000254:growth & development / Q000378:metabolism*; D000818:Animals; D001673:Biodegradation, Environmental; D002857:Chromium / Q000737:chemistry* / Q000302:isolation & purification* / Q000378:metabolism / Q000633:toxicity; D004625:Embryo, Nonmammalian / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D010084:Oxidation-Reduction; D054712:Salinity; D013052:Spectrometry, X-Ray Emission; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013696:Temperature; D014961:X-Ray Diffraction; D015027:Zebrafish / Q000196:embryology
D002857:Chromium; C074702:chromium hexavalent ion
Cellulosimicrobium funkei; Cr(VI) reduction; Haloalkaliphilic; TEM; Zebrafish embryos