Storage Of Dunaliella Salina And Platymonas Helgolandica Var. Tsingtaoensis By Encapsulation-dehydration Under Normal Temperature And Low Temperature

Plant germplasm resources are the material basis for agricultural production and national economic development, and they are related to the survival of mankind and social development, and they are the key status in agricultural sustainable development[1]. But for a long time, because of the diversity of plant germplasm resources and maintain the lack of sufficient attention to the crisis facing germplasm[2]. Therefore, the conservation of plant germplasm resources have became the global concerned topic[3]. Micro-propagation and restrictions on the use of tissue culture techniques, such as preservation of plant germplasm, its biggest advantage is the necessary equipment and conventional tissue culture laboratory is no different from the culture medium, culture environment oxygen content, temperature, moisture content or material change slightly , We can significantly extend the period following the use of cryopreservation freezing technology for long-term stability and preservation of plant germplasm resources to provide an effective approach, but for various reasons most of the current method is based on the study, from the practical applications still some distance [4]. At present, there are a variety of preservation methods microalgae, each method has its own advantages.Following the preservation of a simple, in the production and scientific research in practice is still favored; fixed so that preservation of the slow rate of growth of algae, can be used for secondary metabolites Production and sewage treatment; cryopreservation of germplasm maintain genetic stability, the algae species to the survival of the fittest, to facilitate long-term preservation, to minimize pollution, and other advantages[5]. Encapsulation-dehydration at room temperature and low temperature is kept constant and drying technology combined with conventional compared to save the subculture, it's time for more long-term preservation; compared with cryopreservation, it does not need more complex technology and operations The preservation of valuable equipment, and can save a lot of algae. As an integral part of plant germplasm resources, microalgae have the high use efficiency of energy, and they have tiny volume, nutrient-rich, reproducing fast, having strong adaptability to the environment and culturing easily, and they have widely application in human life and production practice[6]. Especially the microalgae for marine food have an important role in seedling production of fish, shrimp and seashell[7]. And it is very important to conserve plant germplasm resources in the cultivation and application of microalgae[8-11], because the technique of conserving plant germplasm resources is the basic and crucial aspect in the cultivation and further application of microalgae.Dunaliella salina and Platymonas helgolandica var. tsingtaoensis were preserved separately by encapsulation-dehydration under normal temperature and low temperature. Algal cells in early stationary phase were encapsulated in 3% Ca-alginate beads with 30‰NaCl, the beads in different cell density were desiccated with silica gel, then were preserved under normal temperature and low temperature. The main factors influencing the algal viability, such as different temperature, illumination intensities, the water content of beads, cell density, the volume of sealed plastic packing and the outer material of sealed plastic packing, were studied, and the comparison of the effect of conservation between the two microalgae. The results are as follows:1.1 4 oC in the light, after 6 months, the highest survival rate of the preservation of Dunaliella salina and Platymonas helgolandica var. tsingtaoensis was 55.4% and 87.1% separately; 4oC in the dark, after 18 months, the highest survival rate of the preservation of Dunaliella salina and Platymonas helgolandica var. tsingtaoensis was 18.3% and 32.6% separately.1.2 20 oC in the light, after 6 months, the highest survival rate of the preservation of Dunaliella salina and Platymonas helgolandica var. tsingtaoensis was 52.6% and 76.4% separately; 20oC in the dark, after 18 months, the highest survival rate of the preservation of Dunaliella salina and Platymonas helgolandica var. tsingtaoensis was 13.4% and 28.8% separately.1.3 -30 oC, after 6 months, the highest survival rate of the preservation of Dunaliella salina and Platymonas helgolandica var. tsingtaoensis was 37.3% and 18.3% separately; after being processed by 10 percent glycerol kept in -30℃, after 6 months, the highest survival rate of the preservation of Dunaliella salina and Platymonas helgolandica var. tsingtaoensis was 44% and 38.8%.2. As the cell density of the beads is 5×106 cell/ bead, 4oC in the dark ,after 6 months, the highest survival rate of the preservation of Dunaliella salina was 53.7%; as the cell density of the beads is 2.2×106 cell/ bead, 4oC in the dark ,after 6 months, the highest survival rate of the preservation of Platymonas helgolandica var. tsingtaoensis was 83.9%.3. As the volume of sealed plastic packing is 8.1cm3, 4oC in the dark ,the highest survival rate of the preservation of Dunaliella salina was 40.9%; whenever the volume of sealed plastic packing is2.7cm3, 4oC in the dark ,the survival rate of the preservation of Platymonas helgolandica var. tsingtaoensis all can be 75.7%.4. As the outer material of sealed plastic packing is Al-plastics, after 6 months, 4oC in the dark ,the highest survival rate of the preservation of Dunaliella salina and Platymonas helgolandica var. tsingtaoensis was 35.7% and73.7% separately.5. The growth curves and growth rates of Dunaliella salina and Platymonas helgolandica var. tsingtaoensis which were conserved for 6 months and 12 months separately were measured respectively. After two cycles of re-culturing, the growth curves and growth rates of two kinds of microalgae approach to that which were measured with the kinds of microalgae which were not conserved. It illustrates that the two kinds of algae cells can grow and reproduce normally after conserving.Encapsulation– dehydration method is simple, no expensive equipment and applicable to conserve a great deal of algae germplasm for conserving Dunaliella salina and Platymonas helgolandica var. tsingtaoensis under normal temperature and low temperature. Therefore, encapsulation– dehydration method have a wide range of application prospects in the medium-term conservation of microalgae .