Journal of Pure and Applied MicrobiologyVol. 8 No. 6

Detoxification of Carcinogenic Cr (VI) by Combined Action of Bacillus pumilus-S4 and Pseudomonas doudoroffii-S5 in Associated with Hydrophytes

Muhammad Faisal

Department of Microbiology and Molecular Genetics, University of the Punjab, Quaid-e-Azam Campus, Lahore-54590, Pakistan.

Received on 26 June 2014 and accepted on 21 August 2014

 

ABSTRACT

Two chromium resistant bacterial strains (Bacillus pumilus-S4 and Pseudomonas doudoroffii-S5) isolated from tanneries effluent of were reported in this study. Strains resist up to 20 mg K2CrO4 ml-1 on nutrient agar and 2.2 mg ml-1 in acetate minimal medium. Chromate uptake by heat killed cells of Bacillus pumilus-S4 was (5.3 mg g-1 dry wt) 90 min as compared to living cells (25.4 mg g-1 dry wt). Pseudomonas doudoroffii-S5 reduced 14.2 mg Cr (VI) 36 h-1 at an initial concentration of 200 ?g K2CrO4 ml-1. Both strains also release extra cellular proteins in the medium which results extra cellular Cr (VI) detoxification. Cr (VI) removal efficiency of these strains was accelerated by Pistia stratiotes and Eichornia crassipes which provide energy source to strains. Hence these strains could be utilized for the treatment of chromium polluted industrial wastewater in association with metal hyperaccumulator hydrophytes.

Keywords : Bacillus pumilus; Chromium; Eichornia crassipes; heavy metals; Pistia stratiotes; Pseudomonas doudoroffii.