Under environmental stress, most microalgae produce intracellular neutral lipids as a storage mechanism. In the biotechnology industry, these lipids are extracted and converted to microalgal biodiesel; however the extent of the stress is not measured for optimum lipid accumulation. In the series of studies undertaken, Pulse Amplitude Modulated (PAM) fluorometry was used to measure three types of physiological stress on Chlorella sp., a freshwater microalgal species. Biomass and lipid yields were also used as indicators of the induced stress conditions. Firstly, nutrient induced physiological stress and the subsequent synthesis of cellular neutral lipids was investigated.
