氮缺乏下異養(yǎng)和混養(yǎng)微藻產生物柴油
發(fā)布時間：2018-07-15 10:43
【摘要】：隨著原油消耗的加劇,通過各種可持續(xù)技術生產的生物燃料具有很大的應用前景。將微藻油脂通過酯交換反應生產生物柴油作為一種綠色能源技術非常有發(fā)展?jié)摿�。相比較于自養(yǎng)培養(yǎng),異養(yǎng)培養(yǎng)的微藻生長快、油脂產率高,因而吸引了越來越多的關注。為提高微藻的產油率,研究者們采取過許多措施,其中氮缺乏培養(yǎng)作為一種可以刺激微藻產油的方法己被廣泛研究。但缺氮培養(yǎng)雖然可以提高藻細胞的含油率,但是微藻生長速率也會降低,最終導致微藻的產油率也下降了。我們之前的研究發(fā)現(xiàn)充足的磷供應與氮缺乏相結合,可以提高自養(yǎng)體系中小球藻和斜生柵藻的產油率,但其在異養(yǎng)體系中的作用尚不明確。在這項研究中,首先將普通小球藻(Chlorella vulgaris NI[ES-227)進行異養(yǎng)培養(yǎng),采用葡萄糖作為有機碳源,研究它在六種培養(yǎng)基中的生長和產油情況。這六種培養(yǎng)基分別是:氮充足磷充足、氮充足磷限制、氮充足磷缺乏、氮缺乏磷充足、氮缺乏磷限制和氮缺乏磷缺乏。研究發(fā)現(xiàn)在氮缺乏條件下葡萄糖到脂肪酸的轉化率(以COD換算)最高達到了 0.88,而脂肪酸含量則高達89%,其中油酸(C18:1)為主要的脂肪酸成分,占總脂肪酸的50%以上。氮缺乏條件下Cvulgaris的脂肪酸含量顯著高于氮充足條件,而磷的濃度對脂肪酸含量無顯著影響,表明氮饑餓才是異養(yǎng)體系中真正的"脂肪酸觸發(fā)器"。之后考察了柵藻(Scenedesmus obliquus NIES-2280)在異養(yǎng)體系中以乙酸鈉為有機碳源的生長和產油情況。同樣研究了不同氮磷濃度的影響。研究發(fā)現(xiàn)柵藻可以很好地利用乙酸鈉生長并在細胞內積累油脂,經(jīng)過六天的培養(yǎng),缺氮培養(yǎng)基中的柵藻的脂肪酸含量增加到38-48%。值得注意的是,氮缺乏條件下柵藻的脂肪酸產率是氮充足條件下的四倍,而且相比較于磷缺乏和磷限制情況,提供充足的磷還可以進一步提高柵藻的脂肪酸產率至55.9 mg·L-1·d-1。此外缺氮條件下乙酸到脂肪酸的轉化率(18-28%)也遠高于氮充足條件(～7%)。本研究還考察了不同氮磷濃度對以乙酸鈉為有機碳源進行異養(yǎng)的小球藻產油的影響。研究發(fā)現(xiàn)小球藻也可以利用乙酸鈉生長并合成脂肪酸。氮缺乏條件下小球藻脂肪酸含量最高達到了 56%。氮缺乏下小球藻脂肪酸產率是氮充足條件下的三倍,而且充足的磷可以進一步提高脂肪酸是產率至66 mg·L-1·d-1。此外,氮缺乏條件下乙酸到脂肪酸的轉化率也是氮充足條件下的三倍。當控制培養(yǎng)體系的pH在恒定值(7.5、8.0和8.5)時,小球藻的脂肪酸率并未得到進一步提高。本實驗還探索了氮缺乏條件下自養(yǎng)、異養(yǎng)和混養(yǎng)三種培養(yǎng)體系中微藻產油率的關系。實驗發(fā)現(xiàn)當采用乙酸鈉作為異養(yǎng)和混養(yǎng)體系的有機碳源時,混養(yǎng)體系中柵藻的生物量和脂肪酸產率遠遠超過了自養(yǎng)和異養(yǎng)體系的總和,混養(yǎng)體系中脂肪酸產率是自養(yǎng)和異養(yǎng)體系加和的1.64倍。而且混養(yǎng)體系中碳源到脂肪酸的轉化率是異養(yǎng)體系中的兩倍。蛋白組學分析顯示相比較于異養(yǎng)體系,混養(yǎng)體系中TCA循環(huán)活性的提高促進了柵藻細胞內脂肪酸的合成。高油脂含量的微藻可以簡化下游提取過程,類似于大豆油的擠壓提取法。氮缺乏和磷充足的結合可以顯著地提高小球藻和柵藻的產油率以及脂肪酸轉化率。此外,本研究還為通過小球藻和柵藻產油和廢水處理相結合做了堅實的鋪墊。
[Abstract]:With the intensification of crude oil consumption, biofuels produced by various sustainable technologies have great potential applications. The production of biodiesel by transesterification of microalgae through transesterification is very potential for a green energy technology. Compared to the autotrophic culture, microalgae grown in heterotrophic culture are fast growing, and the oil yield is high, thus attracting the high yield of oil. In order to improve the oil production rate of microalgae, researchers have taken a lot of measures. Nitrogen deficiency culture has been widely studied as a method to stimulate the oil production of microalgae. However, the nitrogen deficiency culture can improve the oil content of the algae cells, but the growth rate of microalgae will also be reduced, and the oil production rate of microalgae is also lower. Down. Our previous study found that sufficient phosphorus supply combined with nitrogen deficiency could increase the oil production rate of small and medium algae in the autotrophic system, but its role in heterotrophic systems was not clear. In this study, Chlorella vulgaris NI[ES-227 was first cultured in heterotrophic culture, and glucose was used as a catalyst. The organic carbon source studies its growth and oil production in the six medium. These six medium are: sufficient nitrogen, sufficient phosphorus, sufficient phosphorus, nitrogen deficiency, phosphorus, nitrogen deficiency and nitrogen deficiency. The study found that the conversion rate of glucose to fatty acids (COD conversion) was the highest under the condition of nitrogen deficiency. The content of fatty acids is up to 0.88, and the content of fatty acids is up to 89%, of which oleic acid (C18:1) is the main fatty acid, accounting for more than 50% of the total fatty acids. Under nitrogen deficiency, the content of fatty acids in Cvulgaris is significantly higher than that in nitrogen, but the concentration of phosphorus has no significant influence on the content of fatty acids, indicating that nitrogen hunger is the real "fatty acid" in the heterotrophic system. Then, the growth and oil production of Scenedesmus obliquus NIES-2280 in heterotrophic system with sodium acetate as organic carbon source were investigated. The effects of different nitrogen and phosphorus concentrations were also studied. The study found that the algae can be well used to grow and accumulate oil in cells with sodium acetate, after six days of culture and nitrogen deficiency medium. The fatty acid content of Scenedesmus increased to 38-48%., it is worth noting that the fatty acid yield of the algae is four times that of the nitrogen sufficient condition under the condition of nitrogen deficiency, and the supply of sufficient phosphorus can further increase the fatty acid yield of the algae to 55.9 mg. L-1. And the acetic acid under the condition of nitrogen deficiency. The conversion rate of fatty acids (18-28%) was also much higher than that of nitrogen sufficient conditions (~ 7%). In this study, the effects of different nitrogen and phosphorus concentrations on the oil production of Chlorella with heterotrophic sodium acetate as organic carbon sources were also investigated. The fatty acid yield of Chlorella in 56%. nitrogen deficiency is three times that of the nitrogen sufficient condition, and the sufficient phosphorus can be further increased to 66 mg. L-1. D-1.. The conversion rate of acetic acid to fatty acids under nitrogen deficiency is three times as much as that under the sufficient nitrogen condition. When the pH of the cultured cultured system is at constant value (7.5,8.0 and 8.5), The fatty acid rate of Chlorella was not further improved. This experiment also explored the relationship between the oil producing rate of microalgae in the three cultures of autotrophic, heterotrophic and mixed culture under the condition of nitrogen deficiency. The total of autotrophic and heterotrophic systems combined, the yield of fatty acids in the mixed culture system is 1.64 times as high as that of the autotrophic and heterotrophic system, and the conversion rate of the carbon source to fatty acids in the mixed system is two times that of the heterotrophic system. The improvement of the TCA cycle activity in the mixed culture system promotes the intracellular lipid in the mixed culture system. The synthesis of fatty acids. Microalgae with high oil content can simplify the process of downstream extraction, similar to the extrusion extraction of soybean oil. The combination of nitrogen deficiency and phosphorus sufficient can significantly increase the oil production rate and fatty acid conversion rate of Chlorella and algae. In addition, this study also made a strong combination of Chlorella and algae production and wastewater treatment. A real paving.
【學位授予單位】：中國科學技術大學
【學位級別】：博士
【學位授予年份】：2017
【分類號】：Q949.2;TK6
[Abstract]:With the intensification of crude oil consumption, biofuels produced by various sustainable technologies have great potential applications. The production of biodiesel by transesterification of microalgae through transesterification is very potential for a green energy technology. Compared to the autotrophic culture, microalgae grown in heterotrophic culture are fast growing, and the oil yield is high, thus attracting the high yield of oil. In order to improve the oil production rate of microalgae, researchers have taken a lot of measures. Nitrogen deficiency culture has been widely studied as a method to stimulate the oil production of microalgae. However, the nitrogen deficiency culture can improve the oil content of the algae cells, but the growth rate of microalgae will also be reduced, and the oil production rate of microalgae is also lower. Down. Our previous study found that sufficient phosphorus supply combined with nitrogen deficiency could increase the oil production rate of small and medium algae in the autotrophic system, but its role in heterotrophic systems was not clear. In this study, Chlorella vulgaris NI[ES-227 was first cultured in heterotrophic culture, and glucose was used as a catalyst. The organic carbon source studies its growth and oil production in the six medium. These six medium are: sufficient nitrogen, sufficient phosphorus, sufficient phosphorus, nitrogen deficiency, phosphorus, nitrogen deficiency and nitrogen deficiency. The study found that the conversion rate of glucose to fatty acids (COD conversion) was the highest under the condition of nitrogen deficiency. The content of fatty acids is up to 0.88, and the content of fatty acids is up to 89%, of which oleic acid (C18:1) is the main fatty acid, accounting for more than 50% of the total fatty acids. Under nitrogen deficiency, the content of fatty acids in Cvulgaris is significantly higher than that in nitrogen, but the concentration of phosphorus has no significant influence on the content of fatty acids, indicating that nitrogen hunger is the real "fatty acid" in the heterotrophic system. Then, the growth and oil production of Scenedesmus obliquus NIES-2280 in heterotrophic system with sodium acetate as organic carbon source were investigated. The effects of different nitrogen and phosphorus concentrations were also studied. The study found that the algae can be well used to grow and accumulate oil in cells with sodium acetate, after six days of culture and nitrogen deficiency medium. The fatty acid content of Scenedesmus increased to 38-48%., it is worth noting that the fatty acid yield of the algae is four times that of the nitrogen sufficient condition under the condition of nitrogen deficiency, and the supply of sufficient phosphorus can further increase the fatty acid yield of the algae to 55.9 mg. L-1. And the acetic acid under the condition of nitrogen deficiency. The conversion rate of fatty acids (18-28%) was also much higher than that of nitrogen sufficient conditions (~ 7%). In this study, the effects of different nitrogen and phosphorus concentrations on the oil production of Chlorella with heterotrophic sodium acetate as organic carbon sources were also investigated. The fatty acid yield of Chlorella in 56%. nitrogen deficiency is three times that of the nitrogen sufficient condition, and the sufficient phosphorus can be further increased to 66 mg. L-1. D-1.. The conversion rate of acetic acid to fatty acids under nitrogen deficiency is three times as much as that under the sufficient nitrogen condition. When the pH of the cultured cultured system is at constant value (7.5,8.0 and 8.5), The fatty acid rate of Chlorella was not further improved. This experiment also explored the relationship between the oil producing rate of microalgae in the three cultures of autotrophic, heterotrophic and mixed culture under the condition of nitrogen deficiency. The total of autotrophic and heterotrophic systems combined, the yield of fatty acids in the mixed culture system is 1.64 times as high as that of the autotrophic and heterotrophic system, and the conversion rate of the carbon source to fatty acids in the mixed system is two times that of the heterotrophic system. The improvement of the TCA cycle activity in the mixed culture system promotes the intracellular lipid in the mixed culture system. The synthesis of fatty acids. Microalgae with high oil content can simplify the process of downstream extraction, similar to the extrusion extraction of soybean oil. The combination of nitrogen deficiency and phosphorus sufficient can significantly increase the oil production rate and fatty acid conversion rate of Chlorella and algae. In addition, this study also made a strong combination of Chlorella and algae production and wastewater treatment. A real paving.
【學位授予單位】：中國科學技術大學
【學位級別】：博士
【學位授予年份】：2017
【分類號】：Q949.2;TK6
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