發(fā)布時間：2018-12-13 15:40

【摘要】：富油微藻能夠有效地利用太陽能生產(chǎn)生物柴油,從而實現(xiàn)從無機碳到有機碳的綠色轉(zhuǎn)化。然而,在提高油脂產(chǎn)量的同時降低微藻培養(yǎng)過程的能耗,是實現(xiàn)微藻生物柴油商業(yè)規(guī)�；a(chǎn)的關(guān)鍵。本文選擇能夠耐受較高濃度CO2的Chlorella sp.作為模型生物,探討了在氣升式光生物反應(yīng)器中微藻培養(yǎng)條件的優(yōu)化及能量利用效率提高的問題,并對下游脂質(zhì)提取技術(shù)和脂肪酸分析進行初步研究。與以往許多相關(guān)研究不同,本文從能量利用而不僅是生物產(chǎn)量的角度來考察整個培養(yǎng)過程,希望為以微藻為原料的生物柴油生產(chǎn)提供有價值的借鑒。通過對比不同CO2濃度和光照條件下Chlorella sp.生長情況,發(fā)現(xiàn)CO2濃度提高和光照強度的增大都能顯著促進其生長速率的提高。同時光源會影響碳源的利用,因光照強度的差異,外置光源和內(nèi)置光源的最適二氧化碳濃度分別為10%(v/v)和5%(v/v),最大生物量濃度分別為3.68 g/L,0.47 g/L。當保持CO2濃度為5%時,Chlorella sp.在光強為15.6 W/m2時獲得最大生物量濃度和最大生物產(chǎn)量,分別為3.63g/L和246.35 mg/(L·d)。由于光照較弱,內(nèi)置光纖的凈產(chǎn)量僅為28.30 mg/(L·d),然而與外置光源相比側(cè)光光纖能夠?qū)⒐飧行У胤稚⒂谂囵B(yǎng)基中,其光能利用率大大提高。消耗相同能量時,內(nèi)置光源系統(tǒng)的生物產(chǎn)量較外置光源提高了8.6～25.6倍,在適宜的通氣速率下(0.6 L/min),單位能耗生物產(chǎn)量最高可達4.40g/(W·d)。氮饑餓能促進脂質(zhì)積累但不利于生物產(chǎn)量的提高,缺乏氮源時Chlorella sp.可能利用葉綠素等作為胞內(nèi)氮源,隨著氮饑餓的延長葉綠素a濃度降低。當培養(yǎng)基中NaNO3和檸檬酸鐵銨濃度分別為1.5 g/L和6 mg/L時,脂質(zhì)產(chǎn)量可達到最大值5.66 mg/(L·d)。 Chlorella sp也能夠在有機物和光源同時存在時進行混合代謝,在模擬生活污水中比生長率及油脂產(chǎn)量分別達到0.0033d-1和6.96 mg/(Ld),污染物去除率達到95%以上。研磨、超聲、反復凍融和酸熱均能達到不同程度的細胞破壁效果,其中超聲處理的破壁率最高達到65.25%。四種有機溶劑中,乙醇溶劑的提取效果最優(yōu),在60。C時獲得22.00%的最大油脂得率。Chlorella sp.的脂肪酸中C16和C18占主要優(yōu)勢,多元不飽和脂肪酸酸含量相對較少,能夠滿足一些商用生物柴油的標準。另外,不同提取溶劑和培養(yǎng)條件均會對脂肪酸組成和含量產(chǎn)生影響。因此,我們可以根據(jù)需求定向地選擇有機溶劑和培養(yǎng)條件來優(yōu)化生物柴油產(chǎn)品的品質(zhì)。
[Abstract]:Oil rich microalgae can effectively use solar energy to produce biodiesel, thus realizing the green conversion from inorganic carbon to organic carbon. However, the key to commercial production of microalgae biodiesel is to increase oil production and reduce energy consumption in microalgae culture process. In this paper, we select Chlorella sp. which can tolerate higher concentration of CO2. As a model organism, the optimization of microalgae culture conditions and the improvement of energy use efficiency in an air-lift photobioreactor were discussed, and the downstream lipid extraction techniques and fatty acid analysis were preliminarily studied. Different from many previous studies, the whole culture process was investigated from the point of energy utilization, not just biological yield, in order to provide valuable reference for biodiesel production using microalgae as raw material. Chlorella sp. was compared under different CO2 concentrations and illumination conditions. It was found that the increase of CO2 concentration and light intensity could significantly increase the growth rate. At the same time, the light source will affect the use of carbon source. Because of the difference of light intensity, the optimum carbon dioxide concentration of external light source and built-in light source is 10% (v / v) and 5% (v / v), respectively, and the maximum biomass concentration is 3.68 g / L, respectively. 0.47 g/L. , Chlorella sp. when the concentration of CO2 is kept at 5 Maximum biomass concentration and maximum biomass yield were obtained at a light intensity of 15.6 W/m2, 3.63g/L and 246.35 mg/ (L d)., respectively. The net output of built-in optical fiber is only 28.30 mg/ (L d), due to weak illumination. Compared with external light source, side-light fiber can disperse light more effectively in medium, and its light energy utilization rate is greatly improved. When the energy consumption is the same, the biological output of the built-in light source system is increased by 8.6U 25.6 times than that of the external light source. At the appropriate ventilation rate (0.6 L/min), the biological output per unit energy consumption can reach the maximum 4.40g/ (W d). Nitrogen starvation can promote lipid accumulation, but it is not conducive to the increase of biological yield. Chlorella sp. is lack of nitrogen source. Chlorophyll was probably used as a source of intracellular nitrogen, and the concentration of chlorophyll a decreased with the prolongation of nitrogen starvation. When the concentration of NaNO3 and ammonium ferric citrate were 1.5 g / L and 6 mg/L, respectively, the lipid production reached the maximum value of 5.66 mg/ (L d). Chlorella sp can also be mixed metabolized when organic matter and light source exist at the same time. In simulated domestic sewage, the specific growth rate and oil yield can reach 0.0033d-1 and 6.96 mg/ (Ld), pollutant removal rate of more than 95% respectively. Grinding, ultrasonic, repeated freezing and thawing and acid heat can achieve different degrees of cell wall breaking effect, among which ultrasonic treatment can achieve the highest broken wall rate of 65.25%. Of the four organic solvents, ethanol was the most effective solvent, and the maximum oil yield of 22.00%. Chlorella sp. was obtained at 60.C. C16 and C18 are the main fatty acids, and the polyunsaturated fatty acid content is relatively low, which can meet the standard of some commercial biodiesel. In addition, the composition and content of fatty acids were affected by different extraction solvents and culture conditions. Therefore, we can select organic solvents and culture conditions to optimize the quality of biodiesel products.
【學位授予單位】：大連理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TE667

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相關(guān)期刊論文 前1條

1 蘇貞峰;薛升長;康瑞娟;石紹淵;叢威;蔡昭玲;;平板式光生物反應(yīng)器培養(yǎng)液混合強度對螺旋藻生長的影響[J];中國生物工程雜志;2009年03期

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本文編號：2376783