Growth and ATP levels inPorphyridium purpureum(Rhodophyceae, Bangiales) cultured in the presence of surfactants

Abstract

Growth and ATP levels were studied in the unicellular red alga Porphyridium purpureum cultured on a synthetic agar medium in the presence of seven different commonly used synthetic surfactants. The surfactants were used in concentrations of 0–50 ppm; the alga did not tolerate higher concentrations of the surfactants. Of the surfactants tested, three “mild” compounds (sodium desoxycholate, Synperonic NP9 (a nonyl phenol ethoxylate) and Triton X-100) did not change the normal ATP levels found in control algae (30–45 μg ATP gdw-1). In contrast, the surfactants Ufasan 65 (a linear alkylbenzene sulphonate, LAS) and Genapol ZRO (a polyglycol ether sulphate) increased the ATP levels markedly at concentrations of 30–40 ppm. A similar large increase was observed at 10 ppm of TEGO-Betain L7 (an amphoteric betaine derivative) and Ungerol N2-70 (an ethoxylated fatty alcohol sulphate). The effects of the three “mild” surfactants on the growth of P. purpureum were not linear: at 50 ppm all were growth-inhibitory, and a...