Brief introduction of microorganisms

Microorganisms are a large class of organisms, including bacteria, viruses, fungi and some small protozoa. Although small, it is closely related to people's lives. Microorganisms are generally divided into the following eight categories: bacteria, viruses, fungi, actinomycetes, rickettsia, mycoplasma, chlamydia and spirochetes. Microorganisms can be described as "ubiquitous, ubiquitous" in nature, covering a variety of beneficial and harmful, widely involved in health, medicine, industry and agriculture, environmental protection and many other fields. The following analyzes the relationship between microorganisms and human beings from the aspects of medical care, industrial production, agricultural production, environmental protection and basic research of life sciences.

(a) Microbes and health care

First of all, microbiology has greatly promoted medical treatment. Influenced by Pasteur's embryo theory, British doctors invented carbolic acid surgical disinfection, which played a great role in reducing surgical infection rate. During the thirty years from 1970s to early 20th century, due to the emergence of various microbiological methods, many pathogenic microorganisms were isolated, such as anthrax, leprosy, streptococcus pneumoniae, typhoid, tuberculosis and Yersinia pestis. After more than ten years' efforts, scientists invented the BCG vaccine made of attenuated Mycobacterium bovis, which gave human beings the initiative in the face of pathogenic bacteria. Through the study of microbial metabolism, it is found that an alkaline dye can inhibit the production of microbial tetrahydrofolate, cause microbial death, and a large number of chemotherapeutic sulfonamides appear. At the beginning of last century, the appearance of penicillin triggered the upsurge of exploring the treasure house of antibiotics, and streptomycin and chloramphenicol appeared one after another. Nowadays, the application of genetically engineered bacteria drugs has brought great medical and commercial value.

Secondly, as a woman who loves beauty in the 2 1 century, beauty is a compulsory course in life, so the focus of natural microbiology and medical care is on microbiology and beauty. Microbial enzymes can regulate blood pressure, gastrointestinal function, immune function, protect liver, treat diabetes, and have the effects of whitening, anti-aging, acne removal, antisepsis and beauty care. Microbial enzymes are probiotics. Probiotics refer to live bacterial preparations and their metabolites that play a beneficial role in improving the microecological balance of the host, thus improving the health level and state of the host. Probiotics exist in every corner of the earth. The beneficial bacteria or fungi in animals mainly include lactic acid bacteria, bifidobacteria, actinomycetes and yeasts. At present, the most powerful bamboo-edge active probiotics in the world include active probiotics composed of the above microorganisms.

(b) Microbes and industrial production

Microorganisms are characterized by many kinds, wide distribution, fast growth, fast reproduction, strong metabolic ability, strong adaptability and easy cultivation. In industrial production, suitable microorganisms can be selected according to their characteristics. Some microorganisms can be used when they are isolated from nature, and some need artificial mutation to obtain mutant strains. At present, the general trend of strains used in fermentation industry is from wild bacteria to mutant bacteria, from natural breeding to metabolic breeding, from induced gene mutation to directional breeding of gene recombination. Due to the development of fermentation engineering itself and the intervention of genetic engineering, algae and viruses are gradually becoming microorganisms in industrial production. Microorganisms commonly used in industrial production

1. bacteria

Bacteria are the most widely distributed and abundant microorganisms in nature, which belong to single-celled prokaryotes and reproduce by typical dichotomy. When the cell grows, the circular DNA chromosome replicates, and the protein and other components in the cell are doubled at the same time, then a horizontal interval is generated in the middle of the cell, the chromosomes are separated, and then the interval divides to form two identical daughter cells. If the diaphragm is not completely separated, chain cells will form.

Bacteria commonly used in industrial production include Bacillus subtilis, Acetobacter, Corynebacterium and Brevibacterium. Used to produce amylase, lactic acid, acetic acid, amino acids and inosinic acid.

2. Yeast.

Yeast is a unicellular eukaryotic organism, which is ubiquitous in nature and mainly distributed in acidic environments with high sugar content, such as fruits, vegetables, nectar and plant leaves, as well as orchard soil. Petroleum yeast is mainly distributed in the soil around the oil field. Yeast is mostly saprophytic, often existing in the form of single cells and reproducing in the form of germination. When the mother cell grows to a certain extent, it begins to germinate. When the bud grows up, the mother cell contracts, forming a diaphragm between the mother cell and the daughter cell, and finally forming two cells with the same size. If the bud does not separate from the mother cell, it will form a chain cell called pseudohypha. At the peak of fermentation production, pseudohyphae often appear.

The yeasts used in industry are: beer yeast, Candida, yeast-like yeast and so on. It is used for brewing wine, making bread, producing lipase and producing yeast protein for food, medicine and feed.

3. mold.

Mold is not a taxonomic term. Fungi that grow on nutrient substrates to form fluffy, reticulate or flocculent hyphae are collectively called molds. Mold is widely distributed in nature, and exists in soil, air, water and organisms. It likes acidic environment, most of which are aerobic, saprophytic and a few are parasitic. Mold has a strong reproductive ability. It reproduces with asexual spores and sexual spores, mostly asexual spores. Its growth mode is that the end of mycelium is elongated, the top is branched and intertwined into a net. The length of mycelium is not only controlled by heredity, but also influenced by environment, and the number of branches depends on environmental conditions. The hyphae either grow dispersedly or in clusters.

Commonly used molds in industry are: Rhizopus, Mucor and Plough of algae, Monascus, Aspergillus and Penicillium of Ascomycetes. They can be used to produce various enzyme preparations, antibiotics, organic acids and steroid hormones.

actinomyces

Actinomycetes are named after their linear colonies. It is a prokaryotic group, widely distributed in nature, especially in weakly alkaline soil rich in organic matter. Most of them are saprophytic and a few are parasitic. Actinomycetes mainly reproduce by asexual spores, and some by mycelium fragments. The latter propagation mode is found in liquid immersion culture. Its growth mode is that the end of mycelium stretches and branches, interweaving into a net structure to become mycelium. The length of mycelium is not only controlled by heredity, but also related to the environment. In liquid immersion culture, due to the shear stress of the agitator, short mycelium with strong branches often forms, or grows in dispersion or in the form of mycelium clusters. Its greatest economic value is that it can produce a variety of antibiotics. More than 60% of antibiotics found in microorganisms are produced by actinomycetes, such as streptomycin, erythromycin, chlortetracycline and gentamicin. Commonly used actinomycetes mainly come from the following genera: Streptomyces, Micromonospora and Nocardia.

5. Basidiomycetes

The so-called basidiomycetes are what people usually call mushroom microorganisms. The utilization of basidiomycete resources is attracting people's attention, such as developing polysaccharides, rubber substances and anticancer drugs. In recent years, some scientists in Japan and the United States have conducted in-depth research on the anti-cancer effect of Lentinus edodes, and found that 1, 2-β- glucosidase and two sugars in Lentinus edodes have anti-cancer effects.

6.seaweed

Algae is an autotrophic microbial resource widely distributed in nature, which is used as human health food and animal feed in many countries. When spirulina is cultured, 60t( 1 ha = 104 m2) can be harvested per hectare, while 4t; When planting soybeans, you can harvest per hectare. In terms of output in protein, spirulina is 28 times that of soybean. Calculated from the output of protein, the protein per hectare of mushrooms is 20 ~ 35 times that of wheat. In addition, CO2 can be converted into oil by algae, and the oil obtained by culturing unicellular algae or other algae can account for 5% ~ 50% of dry cell weight. Synthetic oil, like heavy oil, can be converted into products such as gasoline and kerosene after processing. Some countries set up farms to cultivate unicellular algae, and 60 t petroleum fuel can be obtained by calculating 5% dry matter of carbohydrates (petroleum) per hectare cultivated every year. The application of this technology can also reduce the greenhouse effect caused by the massive emission of carbon dioxide in industrial production. It has also been reported abroad that people get hydrogen energy from "algae farms", which cultivate a large number of algae and use their photosynthesis to release hydrogen to get hydrogen energy.

As a large-scale production, there are the following requirements for strains.

(1) The raw materials are cheap, the target products grow rapidly and the yield is high;

⑵ The culture conditions are easy to control, the enzyme activity is high, and the fermentation period is short;

(3) Strong ability to resist miscellaneous bacteria and phage;

(4) The genetic performance of the strain is stable, it is not easy to mutate and degenerate, and it does not produce any harmful bioactive substances and toxins, thus ensuring safe production.

(c) Microbes and agricultural production

Microbes are closely related to agricultural production. For example, the breeding soil and gastrointestinal tract of animals are complex ecosystems composed of many microorganisms. There are beneficial microorganisms and some harmful microorganisms in this system, such as pathogenic bacteria and spoilage bacteria. These microorganisms interact and influence each other. If the number of beneficial microorganisms increases, the growth and reproduction of harmful microorganisms can be inhibited. According to this phenomenon, people purposefully screened out some beneficial microbial species, and cultivated and propagated them to make beneficial biological bacteria preparations. Applying beneficial biological agents to soil can improve the effective nutrient content of soil, reduce the occurrence of diseases and improve the quality of agricultural products. Such as microbial fertilizer. At present, China is the largest producer and consumer of chemical fertilizers in the world, but chemical fertilizers will weaken crop production capacity, aggravate environmental pollution and waste a lot of scarce resources. Microbial fertilizer plays an irreplaceable role in maintaining and improving soil productivity, improving the quality of agricultural products, reducing the occurrence of pests and diseases, protecting the ecological environment of farmland, and consolidating national grain and food safety. It is of great significance for developing "two high and one excellent" agriculture, realizing "green project" and improving people's living standards. Become an excellent choice for fertilizer in the future.

(d) Microbes and environmental protection

Environmental protection and bioremediation of polluted environment are global strategic tasks in 2 1 century, in which microorganisms can play an irreplaceable role. For example, 1 use microbial fertilizers, pesticides or agricultural antibiotics to replace fertilizers or pesticides that will seriously pollute the environment and cannot be degraded; 2. Using PHB, PHB or polylactic acid produced by microorganisms to produce degradable medical plastics, snack boxes and other products to reduce "white pollution"; 3. Use biochemical activities such as microbial degradation and oxidation to purify domestic sewage; Toxic industrial sewage and domestic organic garbage 4 use microorganisms to detect the pollution degree of the environment, such as Ames method to detect the "three-caused" substances, EMB culture medium to detect the intestinal flora in drinking water and other samples, and luminescent bacteria to detect the pollution degree of water sources.

(5) Basic research in microbiology and life science.

Microbiology has promoted the breakthrough of many important theoretical problems and laid the foundation for the development of molecular biology and molecular genetics. Microbiology has made great contributions to the research technology of life science. Due to the infiltration and development of microbiology disinfection, separation and culture, animal and plant cells can be re-cultured in flat plates or triangular bottles and separated under a microscope. Today, the transformation technology of transgenic animals and plants also comes from the theory and technology of microorganisms. The great discovery of microorganisms has led to the emergence of DNA recombination technology and genetic engineering, which has turned a new page in the whole life science and will also make the dream of human beings to change biology, eradicate diseases and beautify the environment come true. On the one hand, microorganisms have made remarkable progress in crossing and promoting each other with other disciplines. On the other hand, it has made great contributions to the development of the whole life science and occupies an important position in the development of life science.