title: Production of EPS under Cr(VI) challenge in two indigenous bacteria isolated from a tannery effluent.
abstract: Indigenous Cr(VI) reducing bacterial strains Pseudomonas aeruginosa Rb-1 and Ochrobactrum intermedium Rb-2 were evaluated for EPS production under Cr(VI) challenged and free conditions. Strain Rb-2 was more efficient in total EPS production (13.63 mg g(-1)) than Rb-1 (4.15 mg g(-1)) under Cr(VI) stress. Thick covering of capsular material around the cells of both bacterial strains was detected by electron microscopy. Transmission electron micrographs showed the appearance of pilli like structures under chromium stress by two bacteria suggested the possible involvement of this in exchange of hereditary material to increase their chances of survival under stress conditions. FTIR study showed involvement of sulphonate and hydroxyl groups in the binding with Cr(VI) ions. Solid-state (13) C NMR spectra revealed that EPS produced by both strains exhibited structural similarity with the glucan. The partial psl gene sequences of Rb-1 and Rb-2 showed homology with psl gene of Pseudomonas aeruginosa PAO1 and capsular polysaccharide biosynthesis protein of various strains of Pseudomonas. This is the first report on the identification of psl gene from Ochrobacterum in NCBI GenBank database up to our knowledge.
authors: Department of Microbiology and Molecular Genetics, Quaid-e-Azam Campus, University of the Punjab, Lahore, Pakistan.|Department of Biosciences, MEM-Group, University of Helsinki, Finland.
authors: Rida
authors: R
authors: Batool
authors: Department of Biosciences, MEM-Group, University of Helsinki, Finland.
authors: Kim
authors: K
authors: Yrjälä
authors: Department of Applied Sciences, University of Huddersfield, United Kingdom.
authors: Kamran
authors: K
authors: Shaukat
authors: Department of Microbiology and Molecular Genetics, Quaid-e-Azam Campus, University of the Punjab, Lahore, Pakistan.
authors: Nazia
authors: N
authors: Jamil
authors: Department of Microbiology and Molecular Genetics, Quaid-e-Azam Campus, University of the Punjab, Lahore, Pakistan.
authors: Shahida
authors: S
authors: Hasnain
mesh_terms: D001704:Biopolymers / Q000096:biosynthesis* / Q000378:metabolism; D002857:Chromium / Q000378:metabolism*; D005798:Genes, Bacterial; D007220:Industrial Waste; D009682:Magnetic Resonance Spectroscopy; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D042041:Ochrobactrum / Q000302:isolation & purification / Q000378:metabolism*; D011550:Pseudomonas aeruginosa / Q000302:isolation & purification / Q000378:metabolism*; D017550:Spectroscopy, Fourier Transform Infrared; D062065:Wastewater / Q000737:chemistry / Q000382:microbiology*
chemical_list: D001704:Biopolymers; D002857:Chromium; D007220:Industrial Waste; D062065:Wastewater; C074702:chromium hexavalent ion
keywords: Cr(VI) reducing bacteria; Electron microscopy; Exopolysaccharide; FTIR; NMR; psl gene