Variation of ATP content in Scenedesmus dimorphus cells grown in a chemostat culture and its comparison with chlorophyll-A content

The variations of ATP and chl-a contents in Scenedesmus dimorphus cells grown in a chemostat culture under nutrient limitation were investigated. ATP and chl-a contents per algal dry weight varied in the ranges of 0.15–1.64 μg mg^?1 (0.33–3.82 μg mg^?1 as ATP/C ratio) and 0.32–1.32% (7.8–30.8 μg mg^?1 as chl-a/C ratio), respectively, under the conditions of T-N/T-P ratio of 2–50 by weight and dilution rate of 1–4 per day. At every T-N/T-P ratio, both ATP and chl-a contents increased as dilution rate increased. At a given dilution rate, ATP content decreased systematically as T-N/T-P ratio increased, with the only exception at dilution rate of 4 per day. It was considered based on the result that ATP or chl-a can hardly be used successfully as an indicator of algal biomass.