Bacillus subtilis in nutrient broth

[Renata S-T]

Hello Everyone,

Has anyone had a problem with the bacillus not growing properly in the nutrient broth?
We used freshly bought bacteria and inoculated broth bottles with it but after overnight in the incubator it 'grew' thin layer of something looking like a mould..?
It should be cloudy instead.
Please look at the picture attached for reference.

All ideas welcome!
Thank you!
Renata

 

[TeoTech]

Your broth looks very pale, but there is some growth. You could always do a streak plate to test for growth.

 

[Renata S-T]

Your broth looks very pale, but there is some growth. You could always do a streak plate to test for growth.

Thank you for that and we actually did what you're suggesting this morning. Looking for results.
What concentration do you make? We make 2g in 150ml of dH2O.

 

[Alman]

What concentration do you make? We make 2g in 150ml of dH2O.

2.5g per 100ml for me.

 

[TeoTech]

13g/L usually. Not sure why it wouldn't work for you?

 

[TeoTech]

Just an FYI, Bacillus Subtillis does grow a milky white film on top. If you are struggling for results, can I ask at what temp. did you incubate at?

 

[Renata S-T]

Just an FYI, Bacillus Subtillis does grow a milky white film on top. If you are struggling for results, can I ask at what temp. did you incubate at?

Thank you very much for that. We incubate it at 35C

 

[labsleuth]

Thank you very much for that. We incubate it at 35C

You shouldn't be incubating it that high anyway as it's too close to body temperature, but we find room temperature works better than 25 degrees in the oven.

 

[TeoTech]

Thank you very much for that. We incubate it at 35C

You shouldn't be incubating it that high anyway as it's too close to body temperature, but we find room temperature works better than 25 degrees in the oven.

Agreement with @labsleuth don't store between 30 and 40 degrees.

 

[Renata S-T]

It did work nicely on the plate! Thank you guys for your help

 

[JennyNewTechnician]

Slightly off topic - how long would you leave it to get a useable broth? One of the teachers has asked for it next week. I would normally ask for 3-4 weeks lead time.

 

[labsleuth]

Slightly off topic - how long would you leave it to get a useable broth? One of the teachers has asked for it next week. I would normally ask for 3-4 weeks lead time.

24 hours from inoculation, so basically just the day before.

 

[JennyNewTechnician]

24 hours from inoculation, so basically just the day before.

Thank you

 

[ThunderChem]

24 hours from inoculation, so basically just the day before.

Typically, although we got poor growth over 24 hours last year. Could have been a set of geriatric microbes. They got going just fine after another 24 hours though, so make sure that the teacher has some flexibility in case the microbes misbehave!

 

[JennyNewTechnician]

Typically, although we got poor growth over 24 hours last year. Could have been a set of geriatric microbes. They got going just fine after another 24 hours though, so make sure that the teacher has some flexibility in case the microbes misbehave!

Thank you

 

[Paul]

24 hours from inoculation, so basically just the day before.

and it should go cloudy.