氮缺乏下异养和混养微藻产生物柴油
发布时间：2018-07-15 10:43
【摘要】：随着原油消耗的加剧,通过各种可持续技术生产的生物燃料具有很大的应用前景。将微藻油脂通过酯交换反应生产生物柴油作为一种绿色能源技术非常有发展潜力。相比较于自养培养,异养培养的微藻生长快、油脂产率高,因而吸引了越来越多的关注。为提高微藻的产油率,研究者们采取过许多措施,其中氮缺乏培养作为一种可以刺激微藻产油的方法己被广泛研究。但缺氮培养虽然可以提高藻细胞的含油率,但是微藻生长速率也会降低,最终导致微藻的产油率也下降了。我们之前的研究发现充足的磷供应与氮缺乏相结合,可以提高自养体系中小球藻和斜生栅藻的产油率,但其在异养体系中的作用尚不明确。在这项研究中,首先将普通小球藻(Chlorella vulgaris NI[ES-227)进行异养培养,采用葡萄糖作为有机碳源,研究它在六种培养基中的生长和产油情况。这六种培养基分别是: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。研究发现在氮缺乏条件下葡萄糖到脂肪酸的转化率(以COD换算)最高达到了 0.88,而脂肪酸含量则高达89%,其中油酸(C18:1)为主要的脂肪酸成分,占总脂肪酸的50%以上。氮缺乏条件下Cvulgaris的脂肪酸含量显著高于氮充足条件,而磷的浓度对脂肪酸含量无显著影响,表明氮饥饿才是异养体系中真正的"脂肪酸触发器"。之后考察了栅藻(Scenedesmus obliquus NIES-2280)在异养体系中以乙酸钠为有机碳源的生长和产油情况。同样研究了不同氮磷浓度的影响。研究发现栅藻可以很好地利用乙酸钠生长并在细胞内积累油脂,经过六天的培养,缺氮培养基中的栅藻的脂肪酸含量增加到38-48%。值得注意的是,氮缺乏条件下栅藻的脂肪酸产率是氮充足条件下的四倍,而且相比较于磷缺乏和磷限制情况,提供充足的磷还可以进一步提高栅藻的脂肪酸产率至55.9 mg·L-1·d-1。此外缺氮条件下乙酸到脂肪酸的转化率(18-28%)也远高于氮充足条件(～7%)。本研究还考察了不同氮磷浓度对以乙酸钠为有机碳源进行异养的小球藻产油的影响。研究发现小球藻也可以利用乙酸钠生长并合成脂肪酸。氮缺乏条件下小球藻脂肪酸含量最高达到了 56%。氮缺乏下小球藻脂肪酸产率是氮充足条件下的三倍,而且充足的磷可以进一步提高脂肪酸是产率至66 mg·L-1·d-1。此外,氮缺乏条件下乙酸到脂肪酸的转化率也是氮充足条件下的三倍。当控制培养体系的pH在恒定值(7.5、8.0和8.5)时,小球藻的脂肪酸率并未得到进一步提高。本实验还探索了氮缺乏条件下自养、异养和混养三种培养体系中微藻产油率的关系。实验发现当采用乙酸钠作为异养和混养体系的有机碳源时,混养体系中栅藻的生物量和脂肪酸产率远远超过了自养和异养体系的总和,混养体系中脂肪酸产率是自养和异养体系加和的1.64倍。而且混养体系中碳源到脂肪酸的转化率是异养体系中的两倍。蛋白组学分析显示相比较于异养体系,混养体系中TCA循环活性的提高促进了栅藻细胞内脂肪酸的合成。高油脂含量的微藻可以简化下游提取过程,类似于大豆油的挤压提取法。氮缺乏和磷充足的结合可以显著地提高小球藻和栅藻的产油率以及脂肪酸转化率。此外,本研究还为通过小球藻和栅藻产油和废水处理相结合做了坚实的铺垫。
[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.
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：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.
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：Q949.2;TK6
【相似文献】
相关期刊论文 前10条
1 吴庆余;;自养小球藻转化为异养代谢生长后细胞的超微结构与相关生化组成[J];南京大学学报(自然科学版);1993年04期
2 詹发萃;邓家齐;夏宜，
本文编号：2123802
本文链接：https://www.wllwen.com/shoufeilunwen/gckjbs/2123802.html
