| Objective: In recent years, there had been an apparent increase in the occurrence of Phaeocystis globosa in China sea which had a negative impact on ecosystem and aquaculture. P. globosa was shown to produce haemolytic toxin by causing the massive death of marine organisms. So far, many reports on eco-physiology of Phaeocystis globosa and properties of haemolytic toxin were performed, but seldom research focused on the biosynthetic mechanism of haemolytic toxin. In this paper, effects of salinity, temperature, light intensity and N sources on the growth and toxin production of Phaeocystis globosa were assessed. The main objectives of this study were to demonstrate the mechanism of haemolytic toxin production and provide useful information for the evaluation of the ecological risk of Phaeocystis globosa and the preparation of standard haemolytic toxin.Method: Growth and haemolytic toxin production of Phaeocystis globosa under different salinity, temperature and light intensity conditions were assessed by designing orthogonal experiment. Influential factors on the growth and haemolytic toxin production of per Phaeocystis globosa cell were analyzed by ANOVA. Effects of ammonia and urea in different concentrations on the growth and haemolytic toxin production of Phaeocystis globosa were observed.Result: Effect of temperature on the growth and haemolytic toxin production were more prominent than that of salinity or light intensity. When cultivated at 30℃, growth rate of Phaeocystis globosa was higher and more haemolytic toxin was produced but growth period was shorter than those cultivated at 20 or 25℃ with longer growth period and higher cell density. In all combinations of 22,33, 40‰ of salinity, 20,25,30℃ of temperature, 2000,4000,50001x of light intensity, the optimal combinations for haemolytic toxin production and growth rate were as follows: 22‰ of salinity, 30℃ of temperature, 40001x of light intensity and 22‰ of salinity, 30‰ of...
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