title: Impact of environmental stress on biochemical parameters of bacteria reducing chromium.
abstract: Chromium pollution is produced in connection with industrial processes like in tanneries. It has been suggested that bioremediation could be a good option for clean up. The stress effect of variable chromate levels, pHs and growth temperatures on biochemical parameters of two Cr(VI) reducing bacterial strains Pseudomonas aeruginosa Rb-1 and Ochrobactrum intermedium Rb-2 was investigated. Transmission electrone microscopy (TEM) was performed to study the intracellular distribution of Cr(VI). It was observed that initial stress of 1000 μgmL(-1) caused significant enhancement of all studied biochemical parameters at pH 7.0 and growth temperature of 37 °C showing great bioremediation potential of the strains. Transmission electron microscopy revealed that the distribution of chromium precipitates was not uniform as they were distributed in the cytoplasm as well as found associated with the periplasm and outer membrane. Fourier transform infrared spectroscopy showed the possible involvement of carboxyl, amino, sulpohonate and hydroxyl groups present on the bacterial cell surface for the binding of Cr(VI) ions. Cr(VI) stress brought about changes in the distridution of these functional groups. It can be concluded that the investigated bacterial strains adjust well to Cr(VI) stress in terms of biochemical parameters and along that exhibited alteration in morphology.
authors.affiliation: Department of Microbiology and Molecular Genetics University of the Punjab Quaid-e-Azam Campus Pakistan Department of Microbiology and Molecular Genetics, University of the Punjab, Quaid-e-Azam Campus, Pakistan. ; MEM-group Department of Biosciences University of Helsinki Finland MEM-group, Department of Biosciences, University of Helsinki, Finland.
authors.forename: Rida
authors.initials: R
authors.lastname: Batool
authors.affiliation: MEM-group Department of Biosciences University of Helsinki Finland MEM-group, Department of Biosciences, University of Helsinki, Finland.
authors.forename: Kim
authors.initials: K
authors.lastname: Yrjälä
authors.affiliation: Department of Microbiology and Molecular Genetics University of the Punjab Quaid-e-Azam Campus Pakistan Department of Microbiology and Molecular Genetics, University of the Punjab, Quaid-e-Azam Campus, Pakistan.
authors.forename: Shahida
authors.initials: S
authors.lastname: Hasnain
mesh_terms: D002857:Chromium / Q000378:metabolism* / Q000633:toxicity; D003593:Cytoplasm / Q000648:ultrastructure; D004785:Environmental Pollutants / Q000378:metabolism / Q000633:toxicity; D006863:Hydrogen-Ion Concentration; D046529:Microscopy, Electron, Transmission; D042041:Ochrobactrum / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects / Q000648:ultrastructure; D010084:Oxidation-Reduction; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects / Q000648:ultrastructure; D017550:Spectroscopy, Fourier Transform Infrared; D013312:Stress, Physiological; D013499:Surface Properties; D013696:Temperature
chemical_list: D004785:Environmental Pollutants; D002857:Chromium
keywords: Cr(VI); FTIR spectroscopy; TEM; biochemical parameters; pH; temperature