Chromium bioaccumulation potential of edaphic cyanobacterium Nostoc linckia grown on multimetallic systems

Abstract

The purpose of this study was to assess the potential of cyanobacterium Nostoc linckia to accumulate hexavalent chromium during three successive cultivation cycles on multimetallic systems. Cyanobacterium Nostoc linckia (Roth) Born et Flah CNM-CB-03 was grown in a mineral medium and metal ions in different combinations. Cultivation was carried out in Erlenmayer flasks of 1000 mL with a working volume of 700 mL. The following parameters were used: pH of the medium 6.8-7.2, temperature 25-27oC, light intensity of 37-55 μmol photons m-2 s -1, continuous illumination, slow periodic shaking. The amount of inoculum was 0.4 g/L. Each cultivation cycle lasted 12 days. Multimetallic systems Cr/Fe, Cr/Fe/Ni, Cr/Fe/Ni/Zn and Cr/Fe/Ni/Zn/Cu were added to culture medium on the exponential phase of Nostoc growth. The culture of Nostoc linckia demonstrated resistance to multimetallic systems and a high potential for bioaccumulation of Cr(VI) and other metals present. The capacity of cyanobacterium Nostoc linckia to bioaccumulate Cr(VI) from the contaminated medium remained high over three generations, while the uptake of Fe, Ni, Cu and Zn in the biomass increased from generation to generation.