title: Isolation and characterization of Bacillus cereus IST105 from electroplating effluent for detoxification of hexavalent chromium.
abstract: OBJECTIVE
  Electroplating industries are the main sources of heavy metals, chromium, nickel, lead, zinc, cadmium and copper. The highest concentrations of chromium (VI) in the effluent cause a direct hazards to human and animals. Therefore, there is a need of an effective and affordable biotechnological solution for removal of chromium from electroplating effluent.
  
  
  METHODS
  Bacterial strains were isolated from electroplating effluent to find out higher tolerant isolate against chromate. The isolate was identified by 16S rDNA sequence analysis. Absorbed chromium level of bacterium was determined by inductively coupled plasma-atomic emission spectrometer (ICP-AES), atomic absorption spectrophotometer (AAS), scanning electron microscope (SEM), transmission electron microscope (TEM) and energy dispersive X-ray analysis (EDX). Removal of metals by bacterium from the electroplating effluent eventually led to the detoxification of effluent confirmed by MTT assay. Conformational changes of functional groups of bacterial cell surface were studied through Fourier transform infrared spectroscopy.
  
  
  RESULTS
  The chromate tolerant isolate was identified as Bacillus cereus. Bacterium has potency to remove more than 75% of chromium as measured by ICP-AES and AAS. The study indicated the accumulation of chromium (VI) on bacterial cell surface which was confirmed by the SEM-EDX and TEM analysis. The biosorption of metals from the electroplating effluent eventually led to the detoxification of effluent. The increased survivability of Huh7 cells cultured with treated effluent also confirmed the detoxification as examined by MTT assay.
  
  
  CONCLUSIONS
  Isolated strain B. cereus was able to remove and detoxify chromium (VI). It would be an efficient tool of the biotechnological approach in mitigating the heavy metal pollutants.
authors.affiliation: School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, 110 067, India. umeshbiology@gmail.com
authors.forename: Umesh Chandra
authors.initials: UC
authors.lastname: Naik
authors.forename: Shaili
authors.initials: S
authors.lastname: Srivastava
authors.forename: Indu Shekhar
authors.initials: IS
authors.lastname: Thakur
mesh_terms: D001409:Bacillus cereus / Q000302:isolation & purification* / Q000378:metabolism* / Q000648:ultrastructure; D001673:Biodegradation, Environmental; D002857:Chromium / Q000737:chemistry / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics; D004595:Electroplating; D004785:Environmental Pollutants / Q000737:chemistry / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D007220:Industrial Waste / Q000032:analysis*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013052:Spectrometry, X-Ray Emission; D017550:Spectroscopy, Fourier Transform Infrared; D014865:Waste Disposal, Fluid / Q000379:methods
chemical_list: D004269:DNA, Bacterial; D004785:Environmental Pollutants; D007220:Industrial Waste; D012336:RNA, Ribosomal, 16S; D002857:Chromium; C074702:chromium hexavalent ion