（毕业设计论文）《pH对斯达氏酵母发酵生产油脂影响》.doc

pH对斯达氏酵母发酵生产油脂影响 摘 要 本论文研究了在摇瓶中利用木薯淀粉发酵生产油脂的培养条件。深入探讨了pH对酵母菌发酵产油脂的影响。在此基础上，主要研究了用NaOH和HCl调节培养基不同初始pH对斯达氏酵母菌产油和菌体生物量的影响。实验得最佳初始pH后，再向培养基中添加不同浓度的pH缓冲剂CaCO3进行进一步探究。同时，每批发酵120h，在此过程中观察培养过程代谢曲线。实验范围内所得酵母产油的最佳条件是：培养基最佳初始pH为6.0，发酵120小时后生物量为10.58%，油脂产量为4.01g/L；pH缓冲剂CaCO3最佳添加浓度为2.0g/L，120小时后生物量为14.53%，油脂产量4.91g/L。酵母菌在24h～60h生物量和油脂含量快速增长。 关键词： 斯达氏酵母菌；微生物油脂；生长代谢；木薯淀粉；初始pH Effects of pH on lipid accumulation by Lipomyces starkeyi Abstract Microbial production of lipids and oil-producing yeast growth by cofermentation of cassava starch yeast Lipomyces starkeyi were examined in this paper. When cultivated by shaking flask at 30 ℃ and 180rpm for 120h, the influences of the initial pH of culture medium and pH buffer, CaCO3, regulating the pH during fermentation to accumulation was probed. When grown on initial pH of 6.0 under identical conditions, biomass and lipid content were 10.58% and 4.01g/L,respectively. The best concertration of CaCO3 was 2.0g/L,and the biomass was found as high as 14.53%.In the end, the lipid was 4.91g/L. Through the experimental exploration,the factors influencing the lipid accumulation were investigated and the optimum conditions of producing lipid were obtained. Keywords Lipomyces starkeyi；Initial pH；microbial lipids；fermentation conditions；Tapioca starch 目 录 TOC \o 1-3 \h \z \u HYPERLINK file:///E:\\论文\\徐翩%20定稿.doc \l _Toc326530044#_Toc326530044 第1章 绪论 PAGEREF _Toc326530044 \h 1 HYPERLINK file:///E:\\论文\\徐翩%20定稿.doc \l _Toc326530045#_Toc326530045 1.1 引言 PAGEREF _Toc326530045 \h 1 HYPERLINK file:///E:\\论文\\徐翩%20定稿.doc \l _Toc326530046#_Toc326530046 1.2 微生物油脂简介 PAGEREF _Toc326530046 \h 1 HYPERLINK file:///E:\\论文\\徐翩%20定稿.doc \l _Toc326530047#_Toc326530047 1.2.1 微生物油脂合成的机理 PAGEREF _Toc326530047 \h 1 HYPERLINK file:///E:\\论文\\徐翩%20定稿.doc \l _Toc326530048#_Toc326530048 1.2.2微生物油脂合成代谢调控 PAGEREF _Toc326530048 \h 1 HYPERLINK file:///E:\\论文\\徐翩%20定稿.doc \l _Toc326530049#_Toc326530049 1.2.3微生物油脂研究现状 PAGEREF _Toc326530049 \h 3 HYPERLINK file