新闻资讯/NEWS
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Detailed sorting of 8 methods and 8 types of institutions for bacterial strain preservation!Principle: Based on the physiological and biochemical characteristics of the bacterial strain, conditions are artificially created to keep the metabolic activity of the bacterial body in a dormant state. Condition: Select excellent purebred, preferably dormant bodies; Create the most favorable environmental conditions for dormancy, such as reducing the nutrient content of the culture medium, low temperature, drying, oxygen isolation, and adding protective agents. 1、 Methods of bacterial strain preservation
1. Oblique preservation method Principle: Low temperature Method: Store the cultivated slanted bacterial strains in a refrigerator at 4-5 ℃, and regularly transplant them onto a new slanted culture medium for further preservation. The general storage period is 3-6 months. Attention: The temperature of the refrigerator; Evaporation of moisture in the culture medium (using rubber stoppers instead of cotton stoppers). Advantages: Simple and suitable for short-term preservation of bacterial strains in the laboratory. Disadvantages: Multiple passages within a short period of time can easily cause bacterial variation and degradation, increasing the likelihood of infection. Applicable strains: short-term preservation of bacteria, actinomycetes, yeast, filamentous fungi, etc. 2. Puncture preservation method Principle: Low temperature, oxygen deficiency. Storage period: 4-5 ℃, refrigerator storage period 6-12 months. Applicable bacterial species: various aerobic bacteria. The function of liquid paraffin is to prevent dehydration of the culture medium and isolate oxygen. Liquid paraffin preservation method: (adding sterilized liquid paraffin to slanted bacterial strains) is suitable for bacterial strains that cannot use paraffin as a carbon source, such as nitrogen fixing bacteria, mycobacteria, Salmonella, mucor, rhizopus, etc. 3. Solid Qu Preservation Method Applicable strain: Spore producing fungi. This method uses natural agricultural products such as bran, rice, millet, or wheat grains as spore producing culture media to produce a large number of dormant cells (spores) for preservation. Attention: Control appropriate moisture content. Shelf life: 1-3 years. 4. Sand tube drying preservation method Principle: Low temperature and low nutrition. Shelf life: 4-5 ℃ Refrigeration shelf life 1-2 years. Applicable strains: Spore producing filamentous fungi and actinomycetes, as well as spore producing bacteria. The screened, sterilized, and dried sand is used as the storage medium. Silicone, magnetic beads, or porous glass beads can be used, but there are not many microorganisms suitable for these carriers, the storage period is short, and they are not as practical as sandy soil. 5. Vacuum freeze-drying preservation method Principle: Quickly freeze cells at low temperatures to maintain their structural integrity, and then sublime water under vacuum (one of the most effective methods). Steps: Handling of ampoules: sterilization; Protector: Its function is to maintain the vital state of bacterial cells and minimize the freezing damage caused by freeze-drying on microorganisms. Skimmed milk or serum is often used. Preparation of bacterial suspension: Mix with protective agent and place in an ampoule bottle; Freeze drying (using low-temperature alcohol or dry ice below -15 ℃ to freeze quickly, and vacuum pump to dry at low temperatures). Shelf life: Melt seal the ampoule at a low temperature of 4-5 ℃ and store for 5-10 years. Factors that affect the preservation effect: bacterial species, bacterial age, and water content in the sample. Applicable strain: Suitable for various microorganisms. Features: Long shelf life, small variation, wide applicability, ideal preservation method. 6. Liquid nitrogen preservation method Principle: Low temperature. Suspension medium: 10% glycerol or 5% dimethyl sulfoxide. Mechanism: Glycerol or dimethyl sulfoxide can enter cells and protect them by reducing strong dehydration. Glycerol is generally sterilized by high-pressure steam, while dimethyl sulfoxide is best sterilized by filtration. Applicable strain: Suitable for the preservation of all microorganisms, animal and plant cells. Shelf life: Store in liquid nitrogen (-196 ℃) for 5-10 years. Features: The longest preservation period, but the high preservation cost, is only used to preserve strains with high economic value, easy variation, or other methods that cannot be preserved for a long time. 7. Suspension preservation method Principle: Oligotrophic preservation, suspending bacterial strains in nutrient free solutions. Applicable strains: filamentous fungi, yeast like fungi, and intestinal bacteria. Shelf life: Store at 10 ℃ or room temperature (18-20 ℃) for more than 1 year. 8. Low temperature preservation method Method: Add 12ml of bacterial solution to a well sealed spiral tube, seal it, and store it directly in a low-temperature refrigerator. Shelf life: -20 ℃ Shelf life of about 1 year. 2、 Precautions for bacterial strain preservation 1. The state of the strain before preservation Dormant bodies such as spores or spores; Cultivation time: too short, easy to die; Excessive length leads to decreased production performance; Culture temperature: Generally, the most suitable temperature for growth is used to cultivate the bacterial strain until the spores mature for better preservation. 2. Substrate used for bacterial strain preservation The culture medium used for inclined preservation should have a lower proportion of carbon sources and a poorer nutritional content; The preservation of sand and soil pipes requires thorough washing of sand and soil to prevent excessive organic matter from affecting bacterial metabolism or producing toxic substances after sterilization; The protective agents used in freeze-drying contain many substances that have been decomposed or denatured by heating, such as reducing sugars and skim milk. Excessive heating can easily form toxic substances. 3. Damage to cellular structure during operation When freeze-drying, the slow freezing speed can easily lead to the formation of large ice crystals inside the cell, causing damage to the cell structure; The degree of vacuum drying affects cell structure, and the addition of protective agents is to reduce the damage to cell structure caused by freeze-drying. 3、 Bacterial strain preservation institution Common Microbial Strain Conservation and Management Center (CCGMC) Agricultural Microbial Strain Conservation and Management Center (ACCC) Industrial Microbial Strain Conservation and Management Center (CICC) Medical Microbial Strain Collection and Management Center (CMCC) China Antibiotic Strain Conservation and Management Center (CACC) Veterinary Microbial Strain Conservation and Management Center (CVCC) Forestry Microbial Strain Conservation and Management Center (CFCC) China Center for the Collection and Management of Typical Cultures (CCTCC) |