How Does Lead (Pb2+) at Low Concentrations Affect on Spirulina (Arthrospira) platensis

Spirulina (Arthrospira) platensis, a blue-green photoautotrophic alga has widely been used for the production of high valued protein for human and animal feeding as well. The present study focused on bioaccumulation of Pb2+ and its effects on growth of S. platensis. The species was cultured in Zarrouk liquid medium with different concentrations of Pb²⁺ (1, 2, 3, 4 and 5 μg/mL) and incubated for ten days under optimal conditions. Accumulated amount of Pb²⁺ increased with increasing Pb²⁺ concentrations (1.218, 2.254, 2.673, 3.713 and 5.173 mg/g dry weight, respectively for 1, 2, 3, 4 and 5 μg/mL of Pb2+, at 2 days of incubation) and decreased as incubation progressed. Bioconcentration factor (BCF) also reached to the peak (1218, 1127, 888, 928 and 1035 for 1, 2, 3, 4 and 5 μg/mL of Pb²⁺ respectively) at 2 days of incubation followed by a gradual reduction. No marked differences were found in growth measured as optical density at 560 nm. It could therefore be concluded that no remarkable inhibition on growth of S. platensis is shown when cultured in contaminated water with low concentrations of Pb²⁺. Furthermore, the species sounds potential accumulator of Pb²⁺ and thus could be used in detoxifying heavy metal affected aquatic ecosystems.

Key words: bioaccumulation; bioconcentration factor; Pb²⁺; Spirulina platensis

DOI: 10.4038/tare.v10i0.1870

Tropical Agricultural Research & Extension Vol.10 2007 47-52