The Axenic Purification And Research Of Biologic Characteristic Of Heterosigma Akashiwo (Hada)

In this thesis, the biological characteristic of Heterosigma akashiwo, which includedthe axenic purification and physiology characteristics, was studied systematically. In order to purificate Heterosigma akashiwo, different modern biotechnologymethods were adopted which include using antibiotics, centrifugal washing technique,dilution method or the combination of them. Other axenic purification techniques werealso used. The results have showed that currently the best purification method is as follows:add Ciprofloxacin (100μg·L^-1) to the algae liquid in the logarithmic phase, 6hs later addSm (200μg·L^-1),Amp (300μg·L^-1) and Ciprofloxacin (100μg·L^-1), 12hs later repeat theoperation above once again, then add Gen (400μg·L^-1) at 24hs and keep for 6 hours more.This method can remove 99.99% miscellaneous bacteria. The basic biological characteristics, physiological and bio-chemical regularity on thegrowth of Heterosigma akashiwo were studied systematically. The influence of differentnutrient factors on the growth of Heterosigma akashiwo, such as the salt concentration,nitrogen sources, phosphorus sources, microelements and vitamins, were discussed. Theresults showed that the optimal salt concentration to HA is 1³%. The growth ofHeterosigma akashiwo was promoted in some way by nitrogen source (37.5²25mg·L-1),phosphorus source (5⁵0mg·L^-1), N/P (25 or 50), Fe³⁺ 0.013mg·L^-1), EDTA (no lower than0.436mg·L-1), Fe3+/EDTA (0.2), Co2+ 1000μg·L-1), Cu²⁺ (980μg·L^-1), Zn²⁺2+ (110μg·L^-1),Mn²⁺ (630μg·L^-1), Mo⁷⁺ (630μg·L^-1), V_B1 (100μg·L^-1), V_B12 (500ng·L^-1), VH (1000ng·L^-1)respectively. Among them, nitrogen source, phosphorus source, Fe³⁺, EDTA and Zn²⁺ arethe limiting factors in the growth of HA. Without these nutrient factors, the growth of HAwill be inhibited. The limiting concentration was nitrogen source 0⁷.5mg·L^-1, phosphorussource 0⁰.05mg·L^-1, Fe³⁺ 0⁰.0027mg·L^-1, EDTA 0⁰.0044mg·L^-1, and Zn²⁺ 0mg·L^-1respectively. As far as the vitamin is concerned, the union of VH (500ng·L^-1), V_B1 (60μg·L^-1)and V_B12 (400ng·L^-1) is best for the growth of the algae. The orthonogal test was designedto search for the optimal combination of nutrition factors. The result showed the optimalmedium for mixotrophic growth of Heterosigma akashiwo was N/P (50), Fe³⁺/EDTA (0.2),and the union of VH (500ng·L^-1), V_B1 (60μg·L^-1) and V_B12 (400ng·L^-1).