论文总字数：14800字

摘 要

本研究拟采用微生物发酵的手段对木糖母液中的半乳糖进行有效降解，为两步生物转化联产木糖醇和阿拉伯糖的工艺创造条件。首先利用液相色谱法测定了木糖母液的成分，然后通过半乳糖平板指示培养基划线筛选到2株专一消耗半乳糖的菌种A和菌种B，并利用薄层层析、DNS法、间苯三酚－冰醋酸法对菌种的半乳糖代谢特性、木糖母液模拟体系和木糖母液的假丝酵母发酵产物（木糖醇母液）中的半乳糖降解进行解析。研究结果表明：木糖母液的主要成分为：葡萄糖26.07g/L，木糖277.86g/L，半乳糖92.68 g/L，阿拉伯糖214.13g/L，木糖醇5.96 g/L；菌种A和菌种B的半乳糖降解率分别为96.6％、86.6％；菌种A和菌种B能够有效降解木糖母液中的半乳糖，充分保留L-阿拉伯糖，为木糖母液生物联产制备L-阿拉伯糖和木糖醇提供了先决条件。

关键词：木糖母液 半乳糖 热带假丝酵母 降解

Galactose degradation in xylose mother liquor

Abstract

In this study, galactose of xylose mother liquor was effective degraded by microbial fermentation to create the conditions for two-step biotransformation xylitol and arabinose from xylose mother liquor. First, the component of xylose mother liquor were determined by high performance liquid chromatography, and then two galactose-fermenting strains were screened through galactose-indicating plates, and that galactose metabolic properties and galactose degradation from xylose mother liquor simulation system and xylose mother liquor fermentation products (xylitol mother liquor) were analyzed by methods of thin layer chromatography, DNS, phloroglucinol-glacial acetic acid. The results showed that: the main components of xylose mother liquor were glucose 26.07 g/L, xylose 277.86 g/L, galactose 92.68 g/L, arabinose 214.13 g/L, xylitol 5.96 g/L, galactose degradation rates of strain A and strain B separately were 96.6%, 86.6%, strain A and strain B can effectively degrade the galactose of xylose mother liquor, at the same time can fully retain L- arabinose, and that is a prerequisite for the bilogical production of L-arabinose and xylitol from xylose mother liquor.

Key words: Xylose mother liquor; Galactose ; Candida tropicalis; Degradation

目 录

摘要……………………………………………………………………………………………Ⅰ

ABSTRACT…………………………………………………………………………………Ⅱ

第一章 文献综述……………………………………………………………………………1

1.1木糖母液…………………………………………………………………………………1

1.2木糖母液与木糖生产工艺………………………………………………………………1

1.2.1工艺流程……………………………………………………………………………1

1.2.2操作要点……………………………………………………………………………1

1.3半乳糖的生物降解……………………………………………………………………2

1.4木糖母液的半乳糖降解策略……………………………………………………………3

1.5木糖母液的生物利用方法………………………………………………………………3

1.5.1培养基………………………………………………………………………………3

1.5.2培养方法……………………………………………………………………………3

1.5.3分析方法……………………………………………………………………………3

1.6本课题的研究目的和意义………………………………………………………………4

第二章 实验内容……………………………………………………………………………5

2.1 实验材料………………………………………………………………………………5

2.1.1 菌种 ………………………………………………………………………………5

2.1.2 木糖母液 …………………………………………………………………………5

2.1.3 主要试剂 …………………………………………………………………………5

2.2 实验仪器 ……………………………………………………………………………5

2.3 实验方法 ……………………………………………………………………………5

2.3.1 培养基……………………………………………………………………………6

2.3.2 培养条件…………………………………………………………………………6

2.3.3 分析方法…………………………………………………………………………6

2.4 研究内容………………………………………………………………………………8

2.4.1木糖母液成分测定…………………………………………………………………8

2.4.2半乳糖菌种筛选……………………………………………………………………8

2.4.3半乳糖菌种的代谢特性……………………………………………………………8

2.4.4木糖醇母液模拟体系中半乳糖的降解……………………………………………8

2.4.5木糖醇母液半乳糖的降解…………………………………………………………8

第三章 结果与分析 ………………………………………………………………………9

3.1木糖母液成分测定………………………………………………………………………9

3.2半乳糖菌种筛选…………………………………………………………………………9

3.3半乳糖菌种的代谢特性………………………………………………………………10

3.4木糖醇母液模拟体系中半乳糖的降解………………………………………………11

3.5木糖醇母液半乳糖的降解……………………………………………………………12

第四章 结论 ………………………………………………………………………………14

参考文献 ……………………………………………………………………………………15

致谢……… ……………………………………………………………………………………17

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