Properties ofChlorella vulgaris strain adapted to high concentration of ammonium nitrogen.

Chlorella vulgaris is very sensitive to high concentrations of ammonium nitrogen. In medium containing 0.33 g NH4-N/1 its growth is inhibited by 50%. Prolonged incubation of the strain in media inhibiting any increase in cell number enabled the isolation of a strain with enhanced tolerance to high ammonium nitrogen concentration. The strain has been designated Chlorella vulgaris/AA. The concentration of nitrogen inhibiting the growth of the strain by 50% was 195 g NH4-N/1. The acquired character proved stable. The isolated strain also demonstrated increased tolerance to high concentration of urea nitrogen. Chl. vulgaris/AA cells were larger than the cells of the parental strain.