Résumé
Phycocyanin is a major light harvesting accessory pigment of red algae and cyanobacteria. In the light of its many commercial applications in food and pharmaceutical industry, purity of the pigment plays a major role. Pharmaceutical industry demands a highly pure phycocyanin with A620/280 ratio of 4 and food industry a ratio of 2. In the present study phycocyanin was extracted in sodium phosphate buffer (pH 7) after macerating in liquid nitrogen. The crude phycocyanin thus extracted was precipitated with 50% ammonium sulphate, purified by dialysis and finally by gel filtration chromatography. Pure phycocyanin was finally obtained with an A620/A280 value of 4.98.
Sujets)
Rhodophyta/métabolisme , Sulfate d'ammonium/pharmacologie , Protéines bactériennes/métabolisme , Biochimie/méthodes , Chromatographie sur gel , Cyanobactéries/métabolisme , Électrophorèse sur gel de polyacrylamide , Lumière , Azote , Phycocyanine/composition chimique , Extraits de plantes , Spectrophotométrie , SpirulinaRésumé
Isolation of cyanobacteria was attempted from herbicide applied rice soils. The predominant genera were Westiellopsis followed by Anabaena, Nostoc and Oscillatoria. The herbicide tolerance was further tested by growing the cyanobacterial cultures in BG-11 medium supplemented with varying concentrations of the commonly used rice herbicide, viz butachlor under in vitro condition. The chlorophyll-a, phycobiliproteins and ammonia excretion were assessed at periodic intervals. Westiellopsis showed the maximum tolerance followed by Anabaena, Nostoc and Oscillatoria.