Molecular Identification Of Marine Microalgae,Growth Characteristics Of Amphidinium Sp.and Its Super Carbon Chain Compound Yield Optimization

Marine microalgae are an important component of phytoplankton in marine ecosystems.It is widely distributed and diverse,and can be found from tropical to temperate zones.For some marine microalgae,such as Amphidinium,Gambierdiscus and Karlodinium,due to special environment,they can produce a special class of secondary metabolites,namely Super-Carbon-Chain Compounds(SCCCs).SuperCarbon-Chain Compounds have the characteristics of huge molecular weight and numerous chiral centers.However,the extremely low content of such compounds in microalgae makes it difficult to determine their chemical structure,thus the existing microalgal culture conditions need to be optimized to improve the yield of SuperCarbon-Chain Compounds.This thesis is divided into three parts.The first section is the molecular identification of 8 strains of marine microalgae harvested from the sea off Sanya,Hainan Province.Firstly,morphological observation was performed by optical microscopy to record their morphological characteristics,such as cell size,motion characteristics,appearance and shape.Then,using molecular biological methods,their genomes was extracted and the DNA encoding their ribosomal small subunits(18S rDNA)was amplified with specific primers.Finally,Blast sequence comparison was performed using the NCBI database,thus the biological classification of marine microalgae could be determined.By this method,8 marine microalgae were identified:2 strains of Amphidinium,3 strains of Rhodomonas,1 strain of Coolia,1 strain of Moestrupia and 1 strain of Proteomonas.The second section is a study of the growth characteristics of the dinoflagellate Amphidinium sp..Different salinity(20,25,30,35,40 ‰),nutrient concentrations(1/2,normal,2,4 times standard concentration)and vitamin concentrations(1/2,normal,2,4 times standard concentration)were used for the culture,and the cell density and growth rate were recorded.The results of the study showed that the optimal growth conditions of Amphidinium sp.were 30‰ salinity,2 times standard concentration of nutrient solution and 1/2 standard concentration of vitamin.In the third section,the optimal growth conditions of Amphidinium sp.were used as a basis to optimize the yield per unit volume of the Super-Carbon-Chain Compounds of Amphidinium sp.by three factors,including salinity,nutrient solution concentration and vitamin concentration,using an orthogonal test.It was shown that the culture conditions for maximum total yield were salinity 30 ‰,2 times the standard concentration of nutrient concentration and 1/2 standard concentration of vitamin.