Journal of Pollution Effects & Control
Open Access

The cyanobacterium Synechocystis sp., PUPCCC 62: A potential candidate for enzymatic reduction of toxic Cr(VI) to less toxic Cr(III)

International Conference on Pollution Control & Sustainable Environment

April 25-26, 2016 Dubai, UAE

J I S Khattar

Punjabi University, India

Posters & Accepted Abstracts: Pollut Eff Cont

Abstract :

The cyanobacterial strain Synechocystis sp., strain PUPCCC 62 isolated from the Satluj River, Ludhiana, India was resistant to hexavalent chromium up to 200 �?¼M with IC50 to be 100 �?¼M Cr(VI). The organism removed 250 nmol Cr(VI) mg-1 protein in 8 hours from imidazole-HCl buffer under optimized conditions of pH (6.0), temperature (28�?±2oC), biomass load (200 �?¼g protein mL-1) and initial metal concentration (100 �?¼M). The Cr(VI) removal by the organism was light/photosynthesis dependent. Kinetics of Cr(VI) removal by the test organism fitted well with the Lineweaver-Burk plot and showed Vmax of 62.5 nmol Cr(VI) mg-1 protein h-1 and Km of 5.8 �?¼M Cr(VI). Not only pH of the solution, phosphate ions also influenced metal removal as Cr(VI) is taken up by the organism through phosphate transporter. It has been demonstrated that the organism enzymatically reduced Cr(VI) to Cr(III) intracellularly and excreted it outside the cells. The enzyme responsible for Cr(VI) reduction was 50 fold purified through ammonium sulphate precipitation and chromatographic techniques. The purified enzyme has 40 kD molecular weight and shared 69% homology with dihydrofolate reductase of Bifidobacterium mongoliense. This cyanobacaterium/its enzyme can be efficiently exploited for bioremediation of Cr(VI) laden industrial effluents before their discharge in to water bodies.

Biography :

Email: jisk_pbi@rediffmail.com