COPPER AND LEAD COMPLEXATION BY HIGH-MOLECULAR-WEIGHT COMPOUNDS PRODUCED BY SYNURA SP. (CHRYSOPHYCEAE)

The freshwater chrysophyte Synura sp. was grown in batch cultures up t o stationary growth phase, harvested, and the dissolved organic materi al collected. Gas-liquid chromatographic analysis showed that mannose and xylose made up 50% of the total polysaccharide composition. Large amounts of protein were detected in the extracellular material by spec trophotometric assay. The complexation properties (conditional stabili ty constant and total ligand concentration) presented by the polysacch aride were investigated using copper and lead ion selective electrodes for complexometric titrations. Seatchard plot analysis revealed that Synura sp. produces one major ligand characterized by high affinity fo r copper and moderate affinity for lead and another ligand with very l ow affinity for either metal.