Serial dilution separation method
① Take 1 gram of soil sample, put it in an Erlenmeyer flask containing 99 mg of sterile water beside the flame, shake it well to disperse the bacteria.
② Take 1 ml of the above bacterial suspension with a pipette, put it into a test tube containing 9 ml of sterile water, and further dilute it to 1000 times, that is, 10-3 bacterial suspension. According to the 10-fold dilution method, serially dilute to 10-8 (the pipette must be replaced for each dilution).
③Take 3 1ml pipettes to draw 1ml of bacterial suspension from 10-8, 10-7, and 10-6 respectively, and pour them into the culture dishes numbered 10-8, 10-7 and 10-6 respectively Inside, the same dilution is repeated to make 3 petri dishes.Petri Dish 150mm,150mm Petri Dish,cheap petri dish,Plastic Petri Dish
④Pour the nutrient agar medium with a temperature of 45～50℃ into each of the above-mentioned petri dishes, rotate gently to mix the bacterial suspension fully, after solidification, place the petri dishes upside down in a warm place (about 28℃). Observe whether there are microbial colonies on the surface of the medium every day.Petri Dish 150mm,150mm Petri Dish,cheap petri dish,Plastic Petri Dish
⑤ After a certain period of incubation, colonies grow on the culture medium. According to the characteristics of the colonies, we can preliminarily judge which type of microorganisms they belong to, and check under a microscope. If the morphology of the bacteria is consistent, it can be considered that a pure strain has been initially isolated.
⑥ The pure strains obtained from the separation and culture are transferred from the plate medium to the test tube slope medium for cultivation.
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Post time: Nov-18-2021