How do you make liquid bacteria culture?

How do you make liquid bacteria culture?

Select a single colony from your LB agar plate using a sterile pipette tip or toothpick. Swirl the tip or toothpick in the liquid LB + antibiotic. Cover the culture loosely with sterile aluminum foil or a non-airtight lid. Incubate the bacterial culture for 12–18 hours at 37 degrees Celsius in a shaking incubator. The bacteria should grow into large colonies that are visible to the eye.

Make sure that the culture is not exposed to any light during this time. After 18 hours, pour the cultured bacteria into a sterile container and store them at -80 degrees Celsius or colder until needed for analysis or use in an experiment.

Liquid cultures are useful because they can be used directly as inoculums for growing larger amounts of bacteria or they can be frozen for later use. They can also be stored for several months if proper storage conditions are maintained.

Culture media components such as yeast extract, casamino acids, and meat extracts can be added to increase the growth rate or different characteristics of the bacteria. For example, adding 5% (v/v) fetal bovine serum to Luria-Bertani (LB) medium increases the growth rate of E. coli bacteria.

You can also supplement liquid cultures with antibiotics to help control harmful bacteria that may otherwise dominate in pure culture. For example, adding 100 mg/L ampicillin to LB medium prevents the growth of any other bacteria except E. coli.

How do you make bacteria stab?


  1. Fill airtight, autoclavable vials with rubber or teflon caps 2/3 full of stab agar.
  2. Inoculate with a single colony repeatedly poking the inoculating loop into the agar.
  3. Incubate at 37°C for 8-12 hrs until cloudy tracks of bacteria become visible.
  4. Seal tightly and store in the dark at room temperature (15-22°C)

What is the correct way to dispose of microbial cultures?

Dispose of the culture in a biohazard-marked rubbish can. C. Allow the agar to dry in the incubator before discarding it. D. Place the culture in an envelope or other container with no adhering surface and discard in the regular trash.

The correct disposal method will depend on what type of microorganism is in the culture. Most bacterial cultures will not require any special handling after they have been subcultured. They should be disposed of in the normal trash. Viral cultures should never be thrown out with regular trash because they could infect others if they come into contact with them. Follow your local regulations for infectious waste.

Cultures used for testing food samples for microbiological contamination should be treated differently than general laboratory cultures. Food samples may contain toxic chemicals that can kill or injure laboratory animals or people who handle them errorully. Always follow lab safety procedures when working with cultures.

If you are unsure about how to dispose of a culture, please contact a local hazardous materials facility to make sure that they will accept it. They may have additional requirements for cultures obtained from laboratories or hospitals.

How do you prepare stock cultures for bacteria?


  1. Follow the steps for Inoculating an Overnight Liquid Culture.
  2. After you have bacterial growth, add 500 μL of the overnight culture to 500 μL of 50% glycerol in a 2 mL screw top tube or cryovial and gently mix.
  3. Freeze the glycerol stock tube at -80°C.

How do you make a bacterial suspension?

The samples are then ready to be seeded with bacterial suspension. Luria Broth (LB) is a medium for the culture of bacteria. Dissolve 0.65 grams of Luria Broth and 0.75 grams of agar in 50 ml of distilled water to make the agar plate. The petriplates and medium should be autoclaved. Bacteria can also be cultured on solid media such as LB agar plates. The sample should be taken from the patient's nose and put into a sterile tube containing sodium chloride solution or saline. This will kill any viruses present in the sample and allow only the bacteria to grow in the laboratory.

The bacterial concentration in the sample should be determined by using a spectrophotometer. Dilute the sample 1:10,000 in saline or sodium chloride solution and pour it onto a pre-warmed LB agar plate. Spread the diluted sample evenly over the surface of the plate using a sterilized glass rod or stick. Let the plate stand at room temperature for 15 minutes to allow the bacteria to settle down. Using a sterilized knife, cut around the edge of the dish to remove all the excess liquid. Place the plate in a refrigerator and let it cool completely before reading the results.

The presence of bacteria on the plate indicates that there are bacteria in the sample. Only pure cultures of bacteria can be used for identification purposes. That is, only cultures grown from individual colonies on the plate should be tested because mixed cultures cannot be identified correctly.

How do you preserve bacteria culture?

Working bacterial stocks can be streaked onto agar plates and kept at 4 degrees Celsius for daily or weekly usage. To reduce contamination and preserve both the culture and agar fully hydrated, culture plates should be wrapped with laboratory sealing film (plastic or paraffin) and kept upside down (agar side up). Alternatively, cultures can be stored at -80 degrees Celsius in lyophilized form with cryoprotectants such as sucrose.

Cultures should be used within one year unless they are preserved using one of these methods.

How do bacteria grow in home science tools?

You must first create sterile culture dishes before you can grow germs. A 125ml container of nutritional agar can fill roughly 10 petri dishes. Method of Water Bath: Loosen but do not entirely remove the agar bottle cap. Place the bottle in hot water at 170-190 degrees Fahrenheit until the agar is completely liquid. Do not let the water boil or the agar will begin to solidify.

While the agar is cooling, prepare your growth medium by combining the corn syrup, soy sauce, and white vinegar in a bowl to make a sugar solution. This will be your basic growth medium for most foods that you want to grow on lab plates. Some organisms need other substances added to their medium to promote growth. These additives can include meat extract, yeast extract, or minerals such as calcium carbonate or magnesium sulfate. Certain antibiotics also work as growth promoters for adding bacteria. Add the antibiotic to the growth medium before pouring it into dish.

Once the agar has cooled enough to handle, pour it into disposable plastic containers with tight-fitting lids. These can be found anywhere plastic storage containers are sold. Pour the sugar solution over the top of the agar mixture, making sure to get all of it out of the bottle. Stir the mixture until the agar is completely dissolved. The concentration of sugar in this medium is similar to that of fruit juice.

Now you are ready to start culturing!

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Thad Eason

Thad Eason has been a journalist for over 20 years. He's covered everything from crime to the environment. He loves finding creative ways to tell stories that aren't already being covered by the mainstream media.

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