Nitrite uptake by Chlamydomonas reinhardtii cells immobilized in calcium alginate

Abstract

When an initial cell loading of about 30–40 µg chlorophyll (Chl)·g⁻¹ gel and alginate suspension of 3% (w/v) were used for immobilization of Chlamydomonas reinhardtii, the resulting cell beads showed optimum nitrite uptake rate, at 30° C and pH 7.5, of 14 µmol NO ^sup−_inf2 ·mg⁻¹ Chl·h⁻¹, the photosynthetic and respiratory activities being about 120 µmol O₂ produced·mg⁻¹ Chl·h⁻¹, and 40 µmol O₂ consumed ·mg⁻¹ Chl·h⁻¹, respectively. The nitrite uptake activity required CO₂ in the culture and persisted after 8 days of cells immobilization, or in the presence of 0.2 mm ammonium in the medium. Our data indicate that alginate-entrapped C, reinhardtii cells may provide a stable and functional system for removing nitrogenous contaminants from waste-waters.