| Spirulina, a microalgae with high economic value, which has the characteristics of high photosynthetic efficiency, rapid growth, strong environmental adaptability and so on, is one of the few microalgaes that can be cultivated in large scale. It is widely popular because of its rich nutrients and bioactive substances. Functional spirulina rich in specific organic mineral elements was obtained through the biological enrichment and transformation of mineral elements by spirulina, by taking spirulina as biological carriers, adding compounds containing specific mineral elements(such as zinc, selenium, etc.) to the culture medium, in order to play a synergistic role of spirulina and mineral elements and improve its health care function. To obtain an edible functional spirulina, there are many problems to be solved in common culture methods, in which low yield is the key problem of the industrialization of spirulina.This paper selects spirulina platensis as the research object for its high economic value,from the angle of the output of spirulina and the supplementation of zinc and selenium, to study the added amount of Zinc and selenium, medium p H and LED lighting(light wavelength, light intensity, illumination time) on the influences of spirulina growth and zinc, selenium Enrichment, thereby getting the best culture program to promote the growth of zinc and selenium enriched spirulina, in order to provide a theoretical basis and technical support for the large-scale culturing of spirulina. The contents and results are as follows:(1)Effect of zinc supplementation on the spirulina growth.By adding Zn SO4·7H2O in Zarrouk culture medium,the results showed that low concentration of zinc can be added to promote the growth of spirulina,and the high concentration of zinc could inhibit the growth of spirulina.When the zinc concentration was 7mg/L,the growth of spirulina was the best,and the maximum biomass could be 1.719g/L,increasing 11.62%compared with the control group.The order of spirulina biomass W was W7mg/L>W5mg/L>W3mg/L≈W对照组>W9mg/L>W11mg/L>W13mg/L.The content of zinc in spirulina increases with the concentration of zinc,and in the comprehensive consideration,the best concentration of zinc is 7mg/L.(2) Effect of selenium supplementation on the spirulina growth. By adding Na2 Se O3·5H2O in Zarrouk culture medium, the results showed thatcompared with thecontrol group, all the different concentrations of selenium supplementationcould promote the growth of spirulina. The promoting effect first increases with the increasing of the concentration of selenium and then decreases. When the selenium concentration was 10mg/L, the growth of spirulina was the best, and the maximum biomass was 1.568g/L, increasing 17.98% compared with the control group. In different concentration of selenium addition, the content of selenium in spirulina increases with the concentration of selenium. In the comprehensive consideration, the best concentration of selenium is 10mg/L.(3) Effect of p H on the zinc-enriched spirulina growth. The results showed that the biomass of zinc-enriched spirulina first increased and then decreased with the increasing of p H value. When the p H value was 9.0, the biomass of zinc-enriched spirulina was the best, and the maximum biomass could be 1.716g/L, increasing61.77% compared with that of the p H value was 8.0. The zinc content of spirulina first increased and then decreased with the increasing of p H value. When the p H value was 8.5, the zinc content of spirulina reached to the maximum, and then the zinc content decreased fast. In the comprehensive consideration, the best p H value is 9.0.(4) Effect of p H on the Se-enriched spirulina growth. The results showed that the biomass of Se-enriched spirulina increased rapidly when p H value increased from 8.0to 8.5, but after p H value reached to 8.5, the growth rate of spirulina tended to be stable.The selenium content of Spirulina first increased and then decreased with the increasing of p H value. When the p H value was 9.5, the selenium content of spirulina reached to the maximum of 1072μg/g, increasing 31.86% compared with that of the p H value was 8.0. In the comprehensive consideration, the best p H value is 9.5.(5) Effect of LED light on the zinc-enriched spirulina growthand zinc enrichment.The effects of light wavelength, light intensity and illumination time on the growth of spirulina and the biological enrichment of zinc in spirulina were studied by using the LED technology. The results showed that the effect of different LED light wavelengths on the growth of spirulina was red light(655~665nm) > blue light(465~475nm) > green light(522~532nm) > control group > yellow light(570~580nm). Compared with the control group, the final biomasses for red light,blue light, green light and yellow light were increased respectively by about 13.97%,10.12%, 1.44% and-2.88%. The effect of different LED light wavelengths on the growth of zinc enrichment in spirulina was yellow light > green light > blue light >red light > control group. Compared with that of the control group, the zinc contentsof spirulina for yellow light, green light, blue light and red light after the 8 days were respectively increased by about 43.73%, 23.98%, 14.29% and 9.04%. Using LED red light as a light source, in the range of light intensity of 0~10000lx, the biomasses of spirulina were directly proportional to the intensity of red light; in the range of light intensity of 0~8000lx, the zinc content of spirulina was directly proportional to the intensity of red light. In the range of illumination time of 0~6h, the effect of LED red light on the growth and zinc enrichment of spirulina has the synchronous trend with that of growth, which increases with the increase of the illumination time.(6) Effect of LED light on the Se-enriched spirulina growth and selenium enrichment.The effects of light wavelength, light intensity and illumination time on the growth of Se-enriched spirulina and the biological enrichment of selenium in spirulina were studied by using the LED technology. The results showed that the effect of different LED light wavelengths on the growth of Se-enriched spirulina was red light(655~665nm) > blue light(465~475nm) > green light(522~532nm) > control group > yellow light(570~580nm). Compared with the control group, the final biomasses for red light, blue light, green light and yellow light were increased respectively by about 12.56%, 6.19%, 1.16% and-1.79%. The effect of different LED light wavelengths on the growth of selenium enrichment in spirulina was yellow light> blue light> red light > green light> control group. Compared with that of the control group, the selenium contents of spirulina for yellow light, blue light, red light, and green light were respectively increased by about 41.66%, 30.66%, 15.35% and 8.42%.Using LED red light as a light source, in the range of light intensity of 0~10000lx, the biomasses of spirulina were directly proportional to the intensity of red light; in the range of light intensity of 0~8 000 lx, the selenium content of spirulina was directly proportional to the intensity of red light. In the range of illumination time of 0~6h, the effect of LED red light on the growth and selenium enrichment of spirulina has the synchronous trend with that of growth, which increases with the increase of the illumination time. |
PDF Full Text Request