Isolation And Optimization Of Cultivation Of Microalgae For Production Of Biodiesel Under High Concentration Of CO₂ And NO

The dwindling fossil fuels and excessive emissions of greenhouse gases are the two important problems facing the world today. Fossil fuel is still the most consumed early generation of energy; however, the burning of fossil fuels is the main source of greenhouse gases. As a kind of renewable energy, biodiesel can reduce fossil fuel consumption and reduce the content of CO2 in the atmosphere. Compared with other biomass energy, microalgae as raw material to produce the third generation of biodiesel has many advantages, such as:the growth rate of microalgae is higher than other plants, compared with the traditional oil crops some species of microalgae contains more oil However, the microalgae biodiesel has not been large-scale used, the main reason is its high production cost. Using waste water and waste gas cultivate microalgae could realize the recycling of raw material, reduce the production cost and the CO2 in the waste gas could also improve the oil content of microalgae.The microalgae species was isolated from the nature water in Jinan. They were cultured with high concentration of CO2 and NO to study their tolerance to the harmful gas. After the cultivation, their total lipid content and fatty acid content were measured to evaluate their oil-production ability. For the species that could tolerate the high concentration of CO2 and NO, it’s nitrogen and phosphorus removal capacity in campus swage was studied in this paper. The main conclusions are as follows:(1) Three species of indigenous microalgae species were isolated They were identified as Scenedesmus sp., through the molecular phylogenetic and morphological method; and named SDEC-12, SDEC-13 and SDEC-14.(2) When culture with air they could grow normally. Their growth rate were 0.205 d-1、0.169 d-1、0.171 d-1 respectively, and all of their total lipid content were above 27%.(3) The SDEC-13 and SDEC-14 strain were able to grow well under 15% CO2 with the maximum biomass productivity of 0.087 g L-1 d-1 and 0.090 g L-1 d-1, respectively. The three strains showed a similar total lipid content (25.7%-28.25%) and the fatty acid of SDEC-14 strain showed the highest saturated level (76.59%).(4) SDEC-13 was the only strain that could tolerate 200 ppm NO and 15% CO2, while its total lipid content remained unaffected by the NO, so the SDEC-13 strain had the potential to produce biodiesel with flue gas.(5) The denitrification and phosphorus removal ability of Scenedesmus SDEC-13 when cultured with campus sewage was studied in this paper. When cultured by campus sewage with 15%CO2, the growth rate of Scenedesmus SDEC-13 is 0.4 d-1, and the content of nitrogen and phosphrous declined obviously.