I want to maintain the pH of starch hydrolysis during the fermentation of amylolytic microbes by using buffer solutions.
a) Anybody can recommend any suitable buffers to be used for such systems?
b) How do we normally use buffers? For example, if I add 2 L of water to flour, how much buffer solution should I add?
Thank you for your advice!
1) it depends on pH you want to use, but also on the processing. The used pH must be max 1 unit from pK of the buffering substance. E.g. Tris base has pK of 8.2, so you can use Tris buffer only in range 7.2-9.2. It's also important what do you expect to happen in the reaction, whether you expect acidification or the other way. Look up buffering capacity on Wikipedia.
2) usually you prepare buffer and this you use directly for solubilization
You want to grow bacteria in it? For bacteria is usually used growth medium, which contains nutrients and is usually buffered.
Hello,
a) I want to grow some amylolytic fungi's and yeast in the medium, and the pH range should be 4.5 - 6.5. Any recommendations?
b) How can I know which buffer to use so that it will not affect the amount of enzymes produced by the microbes?
There is some points to consider:
1- the optimum pH of fermentation is not necessary optimum for enzymes production
2- So if you don't know this pH , you have to test some pH values in the starting of the culture to determine this value
3- there are buffers for each pH interval : for pH 4.5-6.5 you can use 100 mM phtalate buffer , for pH 6.5-7.5 phosphate buffer (Na or K)...
Good luck
the McIlvaine buffer (phosphate-citrate) is suitable for pH 2 - 8, so technically you could use it, but you should try which pH will be suitable for you.
Yes I think you can use phosphate-citrate buffer with a fixed initial pH value in the aim to determine the value for optimum production.
You can apply statistical experimental design to find optimal conditions of fermentation.
may be the buffer could affect your growth rate
I will sugest to use hydrochloric acid (1M) and ammonia (concentrated solution) or more diluted acid and base solution to ajust your pH. Anyway you should check your pH every 1/2-1 h to be sure that its value is almost constant.
I use these reagents for bacteria (E coli) growth in Fermentor. If you have a pH meter you can used in your culturing flask to control de pH.
Sometimes the type of ion in the medium could have influence not only the value of pH
- Badges
- Science topic
- Similar topics
- Chemistry
- Biochemistry