Investigation of Pb(II) bioremediation potential of algae and cyanobacteria strains isolated from polluted water

Abstract

Algae and cyanobacteria are known to be able to remove a variety of pollutants from water, including toxic metal ions. In this study, algal and cyanobacterial species growing in two polluted water bodies were identified, and the Pb(II) removal ability of these isolated species was investigated. Based on microscopic observations, 27 species were identified, and nine species were isolated as pure cultures. Pb(II) bioremediation of five selected species (Anacystis sp., Chlorella sp. 1, Monoraphidium sp., Phormidium sp., and Uronema sp.) was studied in detail. The mean Pb(II) removal abilities varied among these five species: Phormidium sp. > Monoraphidium sp. > Uronema sp. > Chlorella sp. 1 > Anacystis sp. The Pb(II) tolerance of each species was determined based on the live cell percentage and biofilm formation capacity. Within a period of 3 d, Phormidium sp., Monoraphidium sp., and Uronema sp. showed nearly 90% of survival, and all five species demonstrated biofilm formation capacities exceeding 50%. Furthermore, the Pb(II) removal ability of the five species exhibited a strong positive correlation with the live cell percentage and showed a strong negative correlation with the biofilm formation capacity. In conclusion, Phormidium sp., Monoraphidium sp., and Uronema sp. exhibited high tolerances towards Pb(II) and presented high removal abilities. Thus, these species can be identified as potential sorbents for development of suitable adsorption systems to remove Pb(II) from aqueous solutions.