论文总字数：17096字

摘 要

豆渣是一种常见的固体废弃物，含多种营养成分，然而目前利用率十分低，被大量废弃而造成严重的资源浪费。本研究中，利用里氏木霉（Trichoderma reesei）及黄色毛霉（Mucor flavus）产生的酶系进行豆渣的预发酵，使得豆渣在随后的的赤藓醇发酵中更容易被发酵菌株解脂耶氏酵母菌（Yarrowia lipolytica）所利用。预实验结果表明，Y. lipolytica能够以预处理过的豆渣为碳源产生相当量的赤藓醇，证实了该实验可行性。为进一步提高赤藓醇产量，我们对发酵条件进行了优化。结果发现，T. reesei预发酵的豆渣（简称为TF）作为碳源的最佳添加量为50.0 g/L，M. flavus预发酵豆渣（简称为MF）作为碳源的最佳添加量为40.0 g/L。TF豆渣及MF豆渣发酵培养基中NaCl的最适添加量分别为 20.0 g/L和40.0 g/L NaCl，此时产生的渗透压最有利于赤藓醇生成。添加15 mg/L的Mn² 和6 mg/L 的Cu² ，调节赤藓醇合成途径，同时促进其运出细胞。在30 ℃和200 rpm的发酵条件下进行发酵全程追踪发现，发酵5天后二者的赤藓醇产量均达到峰值，其中TF豆渣赤藓醇的最高产量为33.9 g/L，产率为67.8 %；MF豆渣赤藓醇的最高产量为29.7 g/L，产率为74.3%。上述结果表明豆渣可以作为唯一碳源发酵产赤藓醇，为降低赤藓醇发酵成本和豆渣再利用探索了一条新途径。

关键词：豆渣，霉菌发酵，赤藓醇，解脂耶氏酵母，里氏木霉，黄色毛霉

Abstract: Soybean dreg is a kind of common solid waste, which contains many nutrients. However, its utilization ratio is very low, and it is abandoned in large quantities. In this study, the enzyme systems produced by Trichoderma reesei and Mucor flavus were used in the pre-fermentation of soybean dregs, which made the soybean dregs easier to be used by Yarrowia lipolytica in the subsequent fermentation of erythritol. The experimental results showed that Y. lipolytica could produce a considerable amount of erythritol with the pre-treated soybean dregs as carbon source, which proved the feasibility of the experiment. In order to further improve the yield of erythritol, we optimized the fermentation conditions. The results showed that the optimum addition amount of soybean dregs pre-treated by T. reesei as carbon source was 50.0 g/L, the optimum addition amount of soybean dregs pre-treated by M. flavus as carbon source is 40.0 g/L. The osmotic pressure produced by adding 20.0 g/L NaCl to the fermentation medium of TF soybean dregs and the osmotic pressure produced by adding 40.0 g/L NaCl to the fermentation medium of MF soybean dregs were most favorable for the formation of erythritol. By adding Mn² of 15 mg/L and Cu² of 6 mg/L, the synthesis pathway of erythritol was regulated and its migration was promoted. The whole process of fermentation was traced at 30 ℃ and 200 rpm. It was found that the yield of erythritol reached its peak after 5 days of fermentation, the yield of erythritol from TF soybean dregs was 33.9 g/L, with a yield of 67.8%, and the yield of erythritol from MF soybean dregs was 29.7 g/L, with a yield of 74.3%.The results showed that soybean dregs could be used as the sole carbon source to produce erythritol. This fermentation process was a new way to reduce the cost of erythritol fermentation and reuse of soybean dregs.

Key words: Soybean dregs, erythritol, mold fermentation, Yarrowia lipolytica, Trichoderma reesei, Mucor flavus

目 录

1 前言 4

2 材料和方法 9

2.1 材料 9

2.1.1 菌种 9

2.1.2 原料 9

2.1.3 培养基 9

2.1.4 试剂 10

2.2 方法 10

2.2.1 菌株的活化 10

2.2.2 种子液的培养 10

2.2.3 原料的预处理 10

2.2.4 发酵培养优化 11

2.2.5 赤藓醇产量的测定 11

2.2.6 蛋白的测定 11

2.2.7 还原糖的测定 11

2.2.8 标准曲线的绘制 11

3 实验结果与讨论 13

3.1 豆渣预处理对Y. lipolytica赤藓醇发酵的影响 13

3.2 碳源浓度对Y. lipolytica赤藓醇发酵的影响 14

3.3 NaCl浓度对Y. lipolytica赤藓醇发酵的影响 16

3.4添加Cu² 和Mn² 对赤藓醇发酵的影响 17

3.5 Y. lipolytica发酵产赤藓醇曲线的测绘 18

结 论 20

参 考 文 献 21

致谢 24

1 前言

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