Adsorption and tolerance of Cu2+and Zn2+ by Oocystis borgei

Abstract:

The effect of Cu²⁺, Zn²⁺ on the tolerance and adsorption rate of the microalgae Oocystis borgei was studied. Results show that Zn²⁺ and Cu²⁺ has a significant impact on the growth and the content of chlorophyll a of O.borgei. The growth of the algae was inhibited when the concentrations of Cu²⁺ and Zn²⁺ increased. However, low concentration (<0.001 mg/L amd 0.010 mg/L) of Cu²⁺ and Zn²⁺ improved the growth rate of O. borgei and the synthesis of chlorophyll a. The 96hEC₅₀ of Cu²⁺ and Zn²⁺ are 0.229 mg/L and 17.390 mg/L, respectively. The combination of Cu²⁺ and Zn²⁺ has the highest inhibition (103.881%) when 1.000 mg/L of Cu²⁺ and 50.000 mg/L of Zn²⁺ are added to the culture medium. The Cu²⁺ is more toxic than Zn²⁺. The adsorption rate for Zn²⁺ is 81.444% when the cell abundance is 2.291×10⁸ ind/L, while that for Cu²⁺ is 52.521% when the cell abundance is 2.891×10⁸ ind/L. This is equivalent to 9.469 mg/g (5.208×10^-9 mg/ind) and 2.914 mg/g (1.603×10^-9 mg/ind). No toxic effects are observed at these assimilation rates.