Metal tolerance of an indigenous cyanobacterial strain, Lyngbya putealis

Response of an indigenous cyanobacterial strain (Lyngbya putealis) isolated from contaminated site to increasing levels of copper and cobalt was investigated in single metal systems. This cyanobacterial strain showed better response when the medium was spiked with metal. As compared to cobalt treatment, copper had more favorable effect. In single metal systems (copper or cobalt), metal treatments positively effected the cyanobacterial growth as indicated by higher concentration of the primary and accessory photosynthetic pigment (chlorophyll and phycobiliproteins), and biomass production at 0.5 mg/L (M(0.5)) as compared to that at control (M(0)). Exopolymer production (exopolysaccharides and extracellular proteins) too tended to increase significantly in response to both copper and cobalt in L. putealis and found to be maximum at metal concentration M(2.0). This species also showed increased accumulation of starch and carbohydrates in presence of metal (copper or cobalt) at M(0.1). But the overall response was better for copper as compared to cobalt in single metal systems for almost all the studied parameters which show that the strain offered good protection against copper but was sensitive to cobalt. (C) 2011 Elsevier Ltd. All rights reserved.