摘要：研究如何从两个方面提高乳酸产生双乙酰的问题的这个方面的能力：一个是从突变育种，另一个是发酵条件的优化。主要调查结果如下：乳酸乳球菌双乙酰亚种变种6036作为测试筛选，最终获得高产双乙酰突变株发酵作用诱变剂的作用下出发菌株，将其命名为X-1。的结果表明，该突变体X-1二乙酰产量达到8.55mg/ L时，与原始菌株6036相比提高了5.55倍。在发酵条件中心组合优化的作用，最佳发酵条件乙酰生产：最佳发酵温度为37℃，最适初始pH6.5，接种量2％脱脂乳在11％的浓度，旋转速度为100r/分钟。该方法经过脱脂乳培养基菌株X-1产生双乙酰产量为17.45%。43699

毕业论文关键词：乳酸乳球菌；丁二酮；诱变育种；发酵优化；菌种选育

High yield of natural milk flavor essence strain of composite mutagenesis breeding and its fermentation conditions control research

Abstract: Two studies on how to improve the ability of lactic acid producing diacetyl this topic mainly from the optimization of mutation breeding and fermentation conditions. The main findings are as follows: In Lactococcus lactis subsp diacetyl variant 6036 as the original strain by recombination mutagenesis, combined fermentation test screening ultimately yielding diacetyl mutant strain, named as X-1. The results show that the mutant X-1 diacetyl production reached 8.55mg / L, compared with the original strain 6036 improved 5.55 times., Then fermentation conditions were optimized combination through the center, to determine the optimum fermentation conditions diacetyl production: optimum fermentation temperature is 37 ℃, the optimum initial pH 6.5, inoculation amount 2% skim milk at a concentration of 11% shaking speed 100r / min. After this method the strain X-1 in skim milk medium to produce diacetyl production was 17.45%.

Key words: Lactic acid milk coccus; butanedione; Mutation breeding; Optimization of fermentation; Including breeding. 

目录

1引言 1

1.1 奶香精的简述 1

1.2 奶香精的成分 1

1.3 丁二酮的基本介绍 1

1.3.1丁二酮的制备方法 2

1.3.2 丁二酮含量的检测方法探讨 3

1.4 天然奶香精的分析技术及研究进展和现状 3

1.4.1 研究进展 3

1.5 诱变机理 4

1.5.1 亚硝基胍的诱变机理 4

1.5.2 紫外线诱变机理 4

1.6 研究目的与意义 5

2材料与方法 6

2.1 材料 6

2.1.1 菌种 6

2.1.2 主要试剂及原料 6

2.1.3 主要仪器与设备 7

2.1.4 培养基的配制 7

2.2 实验方法 8

2.2.1 丁二酮标准曲线及样品中丁二酮含量的测定 8

2.2.2 菌株的活化 9

2.2.3 菌株生长特性的测定 9

2.2.4 高产丁二酮菌株的诱变及选育 9

2.2.5 发酵条件的优化 10

3结果与分析 12

3.1 丁二酮标准曲线的测定