论文总字数：22123字

摘 要

影响微生物生长的因素有很多，温度是诸多因素中较为重要的一个，不仅温度过高可能会导致其失活，温度过低也有可能会使其失去活性。如今生物技术被广泛应用环境工程中，如解决城市污水、工厂废水、石油污染等方面的问题。因此，研究可以代谢降解环境污染物的耐低温细菌来代替中温菌对我国环境治理有非常重要的意义，对耐低温菌在环境应用方面有广阔的发展前景。此外，冷藏食品尤其是乳制品中也存在低温细菌，低温菌是影响乳制品质量的主要因素。研究出快速、准确、经济的检测乳制品中低温菌的方法可以有效控制乳制品的腐败速度，延长保质期，减少资源浪费。

本实验选用一种芽孢杆菌，首先研究不同盐度的培养条件对这种芽孢杆菌生长的影响。我们将培养基分成三种盐度，其中高盐度培养基中氯化钠含量为15g/L，中等盐度培养基中氯化钠含量为10g/L，低盐度培养基中氯化钠含量为5g/L，同时保证培养基中其他物质含量不变，用紫外分光光度法对其进行生长动力学评价。然后选用盐度最适合细菌生长的培养基，分别在12℃、18℃、25℃下培养该菌，用紫外分光光度法对其进行生长动力学评价，实验知温度对该芽孢杆菌生长的影响较大。该菌在12℃下生长最缓慢，18℃时生长较快，25℃时生长最迅速。

关键词：低温菌 影响因素 盐度 温度

Effect of low temperature on bacterial growth

Abstract

Many factors affect the growth of microorganisms. Temperature is one of the most important factors. Not only too high temperature may lead to its deactivation, but also too low temperature may lead to its deactivation. Nowadays, biotechnology is widely used in environmental engineering, such as urban sewage, factory wastewater, oil pollution and so on. Therefore, the study of low temperature tolerance that can metabolize and degrade environmental pollutants is very important for bacteria to replace medium temperature bacteria for environmental management, and it has a broad prospect for the research of low temperature tolerance bacteria in the environment. In addition, there are also low temperature bacteria in refrigerated food, especially in dairy products. The main factor affecting the quality of dairy products is low temperature microorganisms. A fast, accurate and economical method for detecting low-temperature bacteria in dairy products can effectively control the corruption rate of dairy products, extend the shelf life and reduce waste of resources.

In this experiment, a kind of bacillus was selected. Firstly, the effect of different salinity medium on the growth of bacillus was studied. We divided the culture medium into three kinds of salinity. The content of sodium chloride in high salinity culture medium was 15g / L, that in medium salinity culture medium was 10g / L, and that in low salinity culture medium was 5g / L. At the same time, ensure that the content of other substances in the medium is unchanged. Then measure the absorbance value. Then select the most suitable salinity from the culture medium for bacterial growth, culture at different temperatures, and evaluate the bacterial growth kinetics by ultraviolet spectrophotometry, from which you can understand the effect of temperature on bacterial growth.

Key Words: Cryogenic bacteria; Influence factor; salinity; temperature

目录

摘要 I

Abstract II

第一章 文献综述 1

1.1研究背景 1

1.2低温微生物的分布 1

1.3低温菌的适冷机制 2

1.3.1细胞膜的适冷机制 2

1.3.2低温促进蛋白的表达和诱导特殊蛋白的合成 3

1.3.3酶的适冷机制 4

1.4低温菌的筛选分离 4

1.5低温菌在环境工程中的应用 5

1.5.1去除城市污水中的COD 5

1.5.2降解污水中的氮和磷 5

1.5.3降解石油烃类物质 6

1.5.4降解氯酚类物质 8

1.6低温菌在食品中的应用 8

第二章 实验内容 10

2.1 实验思路 10

2.2 实验材料 10

2.2.1 实验仪器 10

2.2.2 实验试剂 11

2.3 实验方法 11

2.3.1培养基的配制 11

2.3.2不同盐度培养基中芽孢杆菌的培养 11

2.3.3 不同温度下微生物的培养 12

2.4 实验数据分析 12

2.4.1 不同盐度时芽孢杆菌的生长情况 12

2.4.2 不同温度时芽孢杆菌的生长情况 16

第三章 结论与展望 21

3.1实验结论 21

3.2课题展望 21

参考文献 23

致谢 26

第一章 文献综述

1.1研究背景

影响微生物生长的因素有很多，温度是诸多因素中较为重要的一个，不仅温度过高可能会导致其失活，温度过低也有可能会使其失去活性。当温度降低致零下10°C及以下时，大多数微生物会停止生长甚至失去活性。

表1-1 细菌按生长温度特性分类^[1]

表1-1按照细菌的生长温度特性进行了分类。低温菌本身可以产生特殊功能酶和一些其他物质，它们特有的适冷机制使其能更好的适应低温环境，这也是其分布广泛，具有特有生物活性的原因 ^[2]。

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