Hi,
The point of the question is Sufficient aeration! We used 150 ml media in 250 ml bottles (actual volume around 300 ml), but it is traditionally accepted that it should be maximum 40% (media/flask volume). But this ratio has been applied most of the time with erlenmeyers.
3 important points:
1- We are using bottles (Duran) not erlenmeyers, So the surface area (media/air) won't decrease by increasing the volume.
2- We are constantly shaking the bottles during the incubation (25 oC, 150 rpm)
3- Sterile conditions (no other organisms are present other than the inoculated organism)
Hi Mostafa, it depends on how fast grow your fungi. If it grows fast and demands a lot of oxigen, 1/3 of the bottle is ok. If it is a slow growing fungi demanding low oxigen, then you can use even 1/2
Hi Mostafa,
OUR which is related to microbial doubling time and growth rate may affect the vol ratio, but from my experience, 30-35% would be a good ratio.....
Roberto, Thanks for the answer. So in any case, you are suggesting less than 40% (media/flask) volume ratio. right?
Ali, good to hear from you. the "good" ratio is due to sufficient aeration? do you probably have any scientific article that i can refer to?
Dear Mostafa,
Considering a constant microbial growth rate, more vol of medium is associated with more oxygen consumption rate after some time when the microbial population reaches a certain amount ...So, the aeration is a limiting factor for the vol ratio.....
As per the principles in Biochemical engineering, If we need proper Aeration the media should be 1/5th of the total volume of the container.
Even if we shake that doesn't mean with agitation we don't require aeration, agitation and aeration are two different components.
Thirdly, in case of fungi too as there is Hyphae formation we should prefer the above two for better growth.
HI,THE MOST WORK USE THE RATIO OF 1/4, FOR EXCEMPLE; BOTTLE OF 250ml YOU FILL 50ml OF YOUR SAMPLES .FOR SOLID ECHANTTION you put 10g OF YOUR ECHANTIION IN THE ERLENYER OF 500ml
If agitation is the only way to enhance aeration I would recommand a level of media of 2 to 3 cm, indepndant of the total volume. If you grow filamentous fungi you might experience the formation of spheres rather than a homogenuos distribution of your fungus. In this case growth and aeration is anyway limited to the surface of the sphere. If you grow yeast, in my oppinion all recommandations regarding regular bacteria can be applied.
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