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摘要:天然香料2-苯乙醇的生产越来越受到重视，本论文主要研究以活性酿酒酵母粉为发酵菌种，以L-苯丙氨酸为底物，以木糖代替葡萄糖为碳源，在有氧的条件下，通过发酵的方法得到天然香料2-苯乙醇。该制备方法产生乙醇量极低，乙醇浓度不足以对2-苯乙醇的生物合成明显抑制，并且不存在乙醇和2-苯乙醇对该体系的协同抑制，本源性消除乙醇对2-苯乙醇制备的反馈抑制。通过单因素和响应面设计试验对木糖生物转化天然2-苯乙醇进行工艺研究。优化后培养基组成及培养条件为：木糖18.674g/L，L-苯丙氨酸8.276g/L，KH2PO4 8g/L，NaCl 1g/L,MgSO4 7.048g/L，酵母10g/L；初始pH为7，最适培养温度为25℃，装液量50mL，220r/min振荡培养48h。优化后2-苯乙醇产量达到1.566g/L，比优化前的1.145g/L提高了36.77%5126
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关键词: 木糖；2-苯乙醇；L-苯丙氨酸；微生物发酵;毕业论文
Xylose bioconversion 2 - phenyl ethanol by natural spices
Abstract：The production of natural flavor 2 - phenyl ethanol become more and more concerned. This paper mainly research that activity Saccharomyces yeast strains for the fermentation ,L-phenylalanine as a substrate and xylose as carbon source instead of glucose in aerobic conditions, obtained 2 - phenyl ethanol by fermentation of natural spices. The preparation method produces a very low amount of ethanol, so the ethanol concentration was not sufficient inhibit to 2- phenyl ethanol biosynthesis and there is no exist that ethanol and 2 - phenyl ethanol could synergistic inhibition of the system, to endogenous eliminate the ethanol to preparation of 2 - phenyl ethanol l feedback inhibition. Through single factor experiment and response surface design on xylose biotransformation natural 2 - phenyl ethanol process. The optimized medium composition and culture conditions were: xylose 18.674g / L, L-phenylalanine 8.276g / L, KH2PO4 8g / L, NaCl 1g / L, MgSO4 7.048g / L, yeast 10g / L; Initial pH 7, the optimum incubation temperature is 25 ℃, liquid volume 50mL, 220r/min shaking 48h. Optimization within 2 - phenyl ethanol production reached 1.566g / L, than before optimization of 1.145g / L increased 36.77%
KeyWords：xylose,2 - phenyl ethanol, L-phenylalanine,microbial fermentation
目录
1.绪论 1
1.1 2-苯乙醇概述 1
1.1.1 2苯乙醇的简介 1
1.1.2 2-苯乙醇的市场概况 1
1.1.3生产2-苯乙醇的方法 2
1.1.4国内外生物转化法生产2-苯乙醇的快速发展 3
1.2 木糖概述 4
1.2.1木糖的简介 5
1.2.2木糖代谢机理 5
1.3本课题的意义 5
2.实验物品与方法 6
2.1主要原料与试剂 6
2.2主要仪器 7
2.3菌种 7
2.4生物转化培养基 7
2.5实验方法 7
2.5.1菌种筛选 7
2.5.2单因素实验 8
2.5.3响应面实验 8
2.6分析方法 8
2.6.1 液相色谱法分析发酵液中的2-苯乙醇浓度和L-苯丙氨酸浓度 8
2.6.2 气相色谱法分析发酵液中的乙醇与2-苯乙醇 8
2.6.3木糖含量的测定 9
3. 结果与分析 9
3.1 2-苯乙醇与L-苯丙氨酸的含量测定 9
3.2 2-苯乙醇与乙醇的含量测定 10
3.3 木糖含量标准曲线的绘制 11
3.4 菌种筛选 12
3.5各因素对苯乙醇发酵过程的影响 13
3.5.2 磷酸钾盐浓度对转化合成2-苯乙醇的影响 14