Detergent Phosphorus Effect on Algae

Laboratory studies indicate that the sodium triphosphate ingredients of a syndet (ABS) stimulates the growth of the unicellular alga, Chlorella pyrenoidosa. Other ingredients have no apparent effect on growth. Algal growth prospers at ABS concentrations under 3.6 mg/l, slight inhibitions occur at that point, and larger concentrations are increasingly more inhibiting, with growth being completely inhibited at a concentration of 30 mg/l. The minimum amount of detergent phosphorus required to promote algal growth depends on the intracellular phosphorus content of the algal cells. With phosphorus-starved cells, 0.05 mg/l of detergent phosphorus caused apparent growth and, at a concentration above 0.1 mg/l, algal growth was exponential. Algae is capable of both using sodium triphosphate directly for growth and accelerating the hydrolytic breakdown through extracellular enzymes to less condensed phosphates.