Effect of pH on Growth of Several Freshwater Algae

Abstract

Growth of algae at different initial and constant pH values was studied with bulk culture.Initial pH value in BG11 culture medium was adjusted to 6.0,7.0,8.0,9.0 and 10.0 with either 0.5mol/L NaOH or 0.5mol/L HCL.Constant pH values were kept by addition of 20mmol/L bicine.Results showed that different initial pH values had slight effects on growth of algae,because pH values changed to about 10.0 after 4 days of cultivation,but different constant pH had marked effect on growth of algae.Optimal pH values for Microcystis aeruginosa,Anabaena flos-aquae and Oscillatoria planctonica were 9.0, 8.0～9.0 and 7.0～8.0 respectively while for Scendesmus obliquus,Chlorococcum sp and Chlamydomonas reinhardtii were 9.0～ 10.0,7.0～8.0 and 7.0 respectively.