裂殖壶菌利用糖蜜发酵生产DHA研究
裂殖壶菌利用糖蜜发酵生产DHA研究(任务书,开题报告,论文12300字)
摘 要
二十二碳六烯酸（docosahexaenoic acid,DHA）是对人体非常重要的多不饱和脂肪酸。本研究以预处理后的糖蜜作为裂殖壶菌发酵生产DHA的原料。我们首先探究了不同碳源对DHA发酵的影响，结果表明葡萄糖-果糖混合碳源可以作为裂殖壶菌的底物。在此基础上，采用预处理后的糖蜜进行分批发酵，发现当初始总糖浓度超过100 g/L时，不利于裂殖壶菌的生长和油脂的积累，这可能与糖蜜中的有害成分有关。之后，进行了糖蜜的补料分批发酵，油脂含量和DHA产量分别为18.32 和8.26 g/L。为进一步提高糖蜜生产DHA的效率，开发了以葡萄糖和糖蜜为底物的双阶段培养策略，应用该方法，发酵后的细胞干重、油脂含量和DHA产量分别达到80.54、37.22和17.07 g/L。本研究提出了一种利用低成本甘蔗糖蜜发酵DHA的策略，为微藻DHA的经济生产提供了指导。
关键词：裂殖壶菌 二十二碳六烯酸 糖蜜
Study of DHA production by Schizochytrium sp. using cane molasses
Abstract
Docososahexaenoic acid (DHA) as a polyunsaturated fatty acid has been found many health benefits to human. In this study, the pretreated cane molasses was used as raw material for DHA production by Schizochytrium sp. Firstly, we explored the effects of different carbon sources on DHA fermentation, and the result proved that the mixed carbon source with glucose and fructose can serve as a substrate for Schizochytrium. Secondly, batch fermentation with pretreated molasses as carbon source was performed, and the result showed that, it was not conducive to the growth of cells and the accumulation of oil when the initial total sugar concentration exceeded 100 g/L, which might due to the harmful components in molasses. Furthermore, fed-batch fermentation with pretreated molasses was performed. The oil content and DHA production were 18.32 and 8.26 g/L. Finally, to improve the efficiency of DHA production by cane molasses, a two-stage culture strategy using glucose and molasses as a substrate was developed. Using this method, the final results of dry cell weight, oil content, and DHA yield were 80.54, 37.22 and 17.07 g/L. Therefore, this study proposes a strategy for the DHA production using low-cost cane molasses, which provides guidance for the economical production of microalgae- DHA [来源：http://www.doc163.com]
Key Words: Schizochytrium sp.; docososahexaenoic acid ; cane molasses
目 录
摘 要 I
Abstract II
第一章 文献综述 1
1.1 DHA简介 1
1.1.1 DHA的结构、性质 1
1.1.2 DHA的生理功能 1
1.1.3 DHA的来源 2
1.2裂殖壶菌发酵生产DHA的研究 2
1.2.1裂殖壶菌简介 2
1.2.2 裂殖壶菌利用不同碳源发酵生产DHA的研究进展 3
1.3糖蜜概述 3
1.3.1糖蜜在发酵中的应用 4
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1.3.2糖蜜的处理方法研究 4
1.4本课题的研究目的及意义 5
第二章 实验材料与方法 6
2.1 菌种 6
2.2 实验试剂 6
2.3 实验仪器设备 7
2.4 培养基 8
2.5 培养方法 8
2.6 糖蜜预处理 8
2.7 分析方法 9
第三章 结果与讨论 12
3.1分析方法的建立 12
3.1.1果糖标准曲线的建立 12
3.1.2总糖标准曲线的建立 12
3.1.3 脂肪酸成分分析 13
3.2不同碳源对DHA发酵的影响 13
3.3不同初始糖蜜浓度对DHA发酵的影响 14
3.4糖蜜生产DHA的策略的开发 15
3.4.1使用糖蜜进行补料分批发酵 15
3.4.2葡萄糖和糖蜜作为混合碳源的补料分批发酵 17
第四章 结论 19
第五章 展望 20
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参考文献 21
致谢 27