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1、食品微生物学 FOOD MICROBIOLOGY 霍 乃 蕊 山西农业大学食品科学与工程学院 Food Microbiology Lectured by Huo Nairui College of food science and engineering Introduction What is a microbe? A microbe or microorganism is a member of a large, extremely diverse, group of organisms that are lumped together on the basis of one proper
2、ty - the fact that, normally, they are so small that they cannot be seen without the use of a microscope. The word is therefore used to describe viruses, bacteria, fungi, protozoa and some algae. The observation of microbe need to via the light microscope or EM个体形 态需要借助光学显微镜或电子显微镜观察 。 微生物(microorgan
3、ism)：是存在于自 然界的一大群体形微小、结构简单、肉眼 直接看不见，必须借助光学显微镜或电子 显微镜放大数百倍、数千倍，甚至数万倍 才能观察到的微小生物。 exceptions 1.the fruiting bodies of many fungi such as mushrooms are frequently visible to the naked eye; However, there are a few exceptions, 2. equally, some algae can grow to meters in length. Green algae dinoflagella
4、te Brown algae diatom Red algae algae l The colony or lawn can be seem with the naked eye肉眼可观察到微生物聚集的群体 菌落 或菌苔 simplicity Generally, microbes may be considered as fairly simple organisms. Most of the bacteria and protozoa and some of the algae and fungi are single -celled microorganisms, and even th
5、e multi-celled microbes do not have a great range of cell types. Viruses are not even cells/ just genetic material surrounded by a protein coat, and are incapable of independent existence. 微生物与人类的关系 绝大多数微生物对 人类和动、植物是 有益的，而且有些 是必需的。 1.在自然界中元素的循环 2.在工业方面的作用 3.在农业方面的作用 4.在医药方面的作用 5.生物技术 6.科学研究 只有少数的微生物
6、对人类和动、植物是有害的。 The importance of microbiology lThe environment lMedicine lFood lBiotechnology lresearch lThe environment (1) 1.Microbes are responsible for the cycling of carbon, nitrogen and phosphorus (geochemical cycles), all essential components of living organisms . 2.They are found in associati
7、on with plants in symbiotic relationships. lThe environment (2) 3.Maintain soil fertility and may also be used to clean up the environment of toxic compounds (bioremediation). 4.Some microbes are devastating plant pathogens which destroy important food crops, but others may act as biological control
8、 agents against these diseases. lmedicine The diseasecausing ability of some microbes such as smallpox (Variola virus), cholera (Vibrio cholera bacteria; ) and malaria (Plasmodium protozoa. ) is well known. However, microorganisms have also provided us with the means of their control in the form of
9、antibiotics and other medically important drugs. lFood Microbes have been used for thousands of years, in many processes, to produce food, from brewing and wine making, through cheese production and bread making, to the manufacture of soy sauce At the other end of the scale, microbes are responsible
10、 for food spoilage, and diseasecausing microbes are frequently carried on food. lbiotechnology Traditionally microbes have been used to synthesize many important chemicals such as acetone and acetic acid （丙酮和醋酸). More recently, the advent of genetic engineering techniques has led to the cloning of p
11、harmaceutically important polypeptides and other economically important proteins into microbes, which may then be produced on a large scale. lresearch Microbes have been used extensively as model organisms for the investigation of biochemical and genetical processes as they are much easier to work w
12、ith than more complex animals and plants. Millions of copies of the same single cell can be produced in large numbers very quickly and at low cost to give plenty of homologous experimental material. An additional advantage is that most people have no ethical objections to experiments with these micr
13、oorganisms. Microorganism status in biological classification Five kingdom classification system (五界分类系统)put forward by Whittaker (魏塔科) in 1969 according to different nucleic structure aka.: Animal kingdom (animalia) 动物界 Plant kingdom (plantae) 植物界 Protozoa kingdom (protista) 原生生物界 Fungus kingdom （f
14、ungi） 真菌界 Prokaryote kingdom (monera) 原核生物界 ( Eukaryotic microbes （真核细胞型微生物）细 胞核分化程度高，有核膜和核仁，细胞器完整。如真菌。 Prokaryotic microbes （原核细胞型微生物）细 胞核的分化较低，仅有原始核，无核膜、核仁。细胞器很不完 善。DNA和RNA同时存在。这类微生物众多，有细菌、放线菌 、支原体、衣原体、立克次体、螺旋体。 Noncell type microbes（非细胞型微生物是最小的一类 微生物。无典型的细胞结构，只能在活细胞内生长繁殖。核酸 类型为DNA或RNA。病毒属之。 3 typ
15、es 8 kinds（三型八大类） Microbe types Animalia： some protozoa plantae： some microalgae protista： some protozoa、most alga and myxomycota fungi： yeast and mould procaryotae： bacteria，actinomycete,cyanobacteria Vira：viruses Cell type Microorganisms Non -cell type Microbe types 病毒作为一界被提出的较晚，主要原因是： 病毒和类病毒是生物还是非生物，是原始类型还 是次生类型是长期争论未决的问题； 病毒不是用双命法，分类不用阶元系统。 但经过长期研究发现，病毒和细胞型生物具有共同 特性： 遗传物质是DNA(部分病毒是RNA)； 使用共同的遗传密码。 在此基础上，我国学者于1979年提出将无细胞结构 病毒立为病毒界，从而建立了六界系统。 真菌的形态 杆菌 原核生物常见种类和常见形态（1） 球菌 原和生物常见种类和常见形态（2） 蓝细菌（螺旋藻） 蓝细菌（鱼腥草） 原和生物常见种类和常见形态（3） 古细菌（产甲烷细菌） 细菌（耶尔森鼠疫杆菌） Slime molds（粘菌类生物）孢子体 粘菌类生物
