The Impact Of Key Environmental Factors On The Lima Of Prorocentrum The Growth And Toxin Production

Diarrhetic Shellfish Poison (DSP) is a group of important marine biotoxins produced by harmful algae. Due to the potential impacts of DSP toxins on seafood safety and human health, DSP studies attract much attention from researchers, particularly on the mechanism of DSP toxin production. Prorocentrum lima can produce DSP toxins, and can be cultured in the lab, so it becomes the most important organism for the study of DSP toxin production. In order to find out the effects of key environmental factors on the growth and toxin production of P. lima to optimize the culture conditions, as well as collecting enough P. lima cells for the purification of DSP toxins, we studied characteristics of P. lima on the growth and toxin production under different conditionds of light intensity, temperature, salinity, nutrient and disturbance.The result of the multi-factor experiment on the light, temperature and salinity showed that the salinity had significant influence on the growth of Prorocentrum lima, while temperature and light intensity had no significant effects. When the salinity is 28, the growth rate is up to the maximum. In the experiment to study the effects of N/P ratio (nitrogen to phosphorus) on the growth of P. lima, it was found that the cell density of P. lima at the stationary stage reached the maximum when the N/P ratio was between 12 and 16. However, the N/P ratio had little effect on the growth rate of P. lima. Groups at the extremt N/P ratio condtions, in which P. lima cells were under nutrient limitation of either N or P, had elevated DSP toxin content in the cells. Through the comparative studies on the growth and toxin production properties under the condtions of disturbace and static condition, we found that P. lima had a higher growth rate under the disturbance condition, and the time needed for the algae to enter logarithmic stage and stationary stage was much less than that cultured under the static condition. It was also found that the cellular toxin content of the P. lima cells cultured under disturbance condition was much higher that that cultured under the static condition.In summary, we can see that environmental factors have significant influence on the growth and toxin production of P. lima. Under the optimized conditions of salinity,light and temperature, to culture the P. lima cells under the nutrient limitation condition by disturbance, would be beneficial for the production of DSP toxins. These results provide techniques and methods for the optimization of the culture conditions for P. lima and obtain more Prorpcentrum lima cells, and provide fundamental data for the further analysis of DSP toxin production mechanism in P. lima.