| Since the fossil energy consumption and the global climate are getting more and more serious, research, exploitation and utilization of renewable energy have been the wave of social and economic development. As an important component of renewable energy, biomass energy has caught redoubled attention from various countries in the world. Microalgae is a source of biomass energy which has numerous advantages such as the high photosynthetic efficiency, environmental adaptability, high oil content, high biomass production, short growth cycle and easy to cultivate. Algae with abundant natural resources in Hainan Province where is warm year-round and rich in water resources have great potential value. This study was designed to enrich China's algae collection by exploritating the special algae resources in Hainan, and to establish a core gerplasm collection for microalgae energy development and building a set of effective selective methods for the microalgae with large research and economic value, such as high-biomass, oil content.Three experimental protocols, water titration, dilution, and plate methods, were used for separating and purifying the algal strains from 11 sites. As a result,87 algal strains were obtained, among which 34 were marine microalgae, others are freshwater ones. More than 10 species were preliminary identified by morphological observation as Pediastrum biraditum, Scenedesmus dimorphus, Coelastrum microporum and so on. The strain DWZ-8 was studied in detail. This strain reproduced by autosporulation, the chloroplast divided in a unique way of splitting. There is only one 1.4-2.1μm pyrenoid in the chloroplast, and the thylakoids in the pyrenoid are tubulous with various directions including parallel with the plane of the vertical and crosssection. By using molecular biological methods, we found that in DWZ-8 the nuclear-encoded 18S rDNA, which is 2500bp, contained 2 GI introns, while the chloroplast-encoded 16S rDNA, which is 1488bp, contained no intron. Phylogenetic analysis based on the 18S and 16S rDNA seqeunces positioned this strain in the clade represented by Heveochlorella hainangerisis, but both the 18S and 16S rDNA sequences were very different compared with H. hainangensis and other related species in similarities and exon-intron structure, herefore, the author preliminarily presented DWZ-8 as a new species in the Heveochlorella genus.In this study, a rapid Nile red staining of neutral lipids in algae was developed which can be further used in the preliminary screening of algal strains with high oil content. The method is based on that the florescent intensity of Nile red stained neutral lipids is positively correlated with the lipid content. A microalgae strain Hhw was used as the material. The optimal conditions were obtained by series of gradient tests, which were EX485nm, cell density OD690=0.858, DMSO added 250μl/ml, dyeing 2 min, NR= 1.2μg/ml.A suitable laboratory method was selected from 4 protocols for rapid extraction of crude lipids from microalgae, called improved acid hydrolysis. At the same time, the selection platform integrated Nile red staining microscope observation with extracting directly for high-oil content microalgae was established, and screened the desired ones.Analysis of the fatty acid compositions of 2 strains indicated that the fatty acids of Heveochlorella were relatively simple, consisting mainly 6 types:linoleic acid, oleic acid, stearic acid, myristic acid, palmitic acid, linolenic acid. About 50.4% were unsaturated fatty acids, and 16-18 carbon fatty acids accounted for 96% of the total fatty acids. The main fatty acids of Hhw were linoleic acid, oleic acid, stearic acid, myristic acid, palmitic acid, palmitic acid, linolenic acid, arachidonic acid and EPA. About 40.58% fatty acids in HhW were unsaturated, and 16-18 carbon fatty acids accounted for 86.27% of the total fatty acids. Therefore, lipids from both H. hainangenesis and Hhw are suitable for biodiesel processing.
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