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Biology-Related Homework Help Cell Biology Topic started by: Pono on Dec 6, 2021



Title: How to obtain more bacteria culture from already developed colony in HS medium
Post by: Pono on Dec 6, 2021
I have a freeze-dried lab sample of pure Gluconacetobacter Xylinus (form. Acetobacter Xylinum). I am about to grow this colony of bacteria in a standard Hestrin and Schramm medium (HS) of 1000ml volume. This will allow me to run 10 different experiments (100ml each).

Two questions:

Question 1: Is it possible to take 100ml of medium with already fully developed bacterial culture inside and mix it with 900ml of pure medium to effectively grow another 1000ml of bacterial culture? This process would allow me to keep "cloning" the initial bacterial colony indefinitely without the need of purchasing freeze-dried samples every time I need to run experiments.

Question 2: Is it possible to keep the already fully developed bacterial culture in a 100ml medium for longer periods of time (months)? Bacterial culture will keep growing in a medium up until carbon, nitrogen, and oxygen resources are depleted. What happens after - will it simply die (after approx. 20 days) or will it enter a hibernation state in which addition of fresh nutrients will allow it to grow more?

Thank you.


Title: Re: How to obtain more bacteria culture from already developed colony in HS medium
Post by: bio_man on Dec 6, 2021
Question 1: Is it possible to take 100ml of medium with already fully developed bacterial culture inside and mix it with 900ml of pure medium to effectively grow another 1000ml of bacterial culture?

Yes, it will grow in theory if there's an energy source found within the medium.

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This process would allow me to keep "cloning" the initial bacterial colony indefinitely without the need of purchasing freeze-dried samples every time I need to run experiments.

Yes, good strategy.

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Question 2: Is it possible to keep the already fully developed bacterial culture in a 100ml medium for longer periods of time (months)?

The specific length of time that a culture will remain viable in a given storage condition is dependent upon the bacterial strain. According to this article (https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/gluconacetobacter):

Being isolated and differentiated, Gluconobacter can be maintained on various liquid (beer) and solid media. Table 1 gives a survey on recommended solid media. Agar cultures should be kept at 4 °C and transferred monthly. Strains can be kept frozen at –75 °C in the presence of 24% (v/v) glycerol or dimethyl sulfoxide (10%, v/v). Freeze-dried strains will remain alive for several years.

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Title: Re: How to obtain more bacteria culture from already developed colony in HS medium
Post by: duddy on Dec 6, 2021
The table above discusses freeze drying, but I don't think the OP needs that kind of information.

For short-term storage:

Working bacterial stocks can be streaked onto agar plates and stored at 4°C for daily or weekly use. Culture dishes should be wrapped with laboratory sealing film (plastic or paraffin) and stored upside down (agar side up) to minimize contamination and to keep both the culture and agar properly hydrated. Some bacterial strains can be stored for up to 1 year at 4°C in agar stab cultures.

For long-term storage:

The temperature at which frozen bacteria are stored affects how long they can be stored while remaining viable. Freezing and thawing cells at an appropriate rate and maintaining the frozen stocks at the proper storage temperature help to minimize damage from the freezing process. Also, the greater the cell density, the better the recovery is after thawing the cells. For most bacteria, a density of 107 cells/mL will result in adequate recovery if all conditions are properly maintained.