Vacuum freeze-drying preservation method
Using all the factors that are conducive to the preservation of strains, first freeze the microorganisms at a very low temperature (about -70 ° C), and then use the sublimation phenomenon to remove moisture under reduced pressure (vacuum drying), so that the microorganisms are always in a low temperature, dry, lack Under the condition of oxygen, it is by far one of the most effective methods for the preservation of strains.
It is suitable for long-term preservation of strains, generally it can be stored for several years to more than ten years. But the equipment and operation are more complicated. Operation process: prepare ampoule tube → prepare skimmed milk → prepare strains → prepare bacterial suspension → sub-samples → freezing → vacuum drying → sealing tube → viability test → preservation → activation. The ampoule tube is soaked with 2% HCl, washed with water multiple times, and dried.
Put the label in the ampoule tube, plug the tube with cotton, sterilize at 121 ℃ for 30min, and set aside.
In general, bacteria require a culture of 24-48 hours; yeast needs to be cultured for 3 days; spore-forming microorganisms should be preserved; actinomycetes and filamentous fungi are cultured for 7-10 days.
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