We use alekxandrov medium for isolation of potasium solubilizing bacteria by use of isoluble k minerals (mica, feldspat etc).but why we add Ca3PO4 as phosphate source.Ca3PO4 is sparingly insoluble !!!!!!!!
Can we use soluble phosphates?
thank your Dr. Vijay Singh Meena . but Tricalcium phosphate is insoluble. hence bacteria should solubilize TCP first, in this condition we lose some of bacteria.is it true? can we use soluble phosphate ?
Soluble phosphate hinders the production of siderophores and other compounds important for potassium (and other insoluble compounds) mobilization.
the principle of using Ca3PO4 in this medium in my opinion is to stimulate the production of organic acids by the strain, the indirect ones responsible for the solubilization of Ca3PO4 to make the P available in the medium which has repercussions on potassium solubilization of course.
Thank you Dr.abderrazak.
You mean K is not so vital for bacterial growth? Please explain it....
Dear Mostafa,
I totally agree with Dr. Rfaki Abderrazak . the purp
Dear Mostafa,
Potassium plays a role in the physical and chemical balance of the cell. It is a major cellular cation and cofactor for certain enzymes. So it's a very important element for the bacterial cell. But their role is less important compared to phosphorus in bacterial physiology. That is to say, the priority for the bacterium is to solubilize Ca3PO4 via the secretion of organic acids which also causes an indirect solubilization of insoluble forms of potassium.
Good continuation,
I am going to perform a exprriment using soluble phophate and insoluble phosphates in mediums....
And determine solubility of K
What is you opinion about glucose in mediun.....?!
I think we can use other carbohydrates for stimulating more acid production
What do you think ?
Hello Mostafa,
in my opinion glucose is very important in the medium compared to other Carbohydrates because it is the precursor of gluconic acid, which is the major cause of the solubilization of insoluble mineral phosphate.
So it's better to keep the glucose in the medium,
Good luck,
Dear Dr.abderazak
I dont agree with your opinion because some papers showed by using different sources of C and N solubilization efficiency of bacteria differs.
Dear Mostafa,
I fully agree with you about the variation in the efficiency of solubilization according to the different sources of C and N. But I'm talking about what has been reported in several articles about glucose as the precursor of gluconic acid, the major cause of solubilization of insoluble inorganic phosphate,
Sincerely
the mechanisms used by microorganisms to solubilize phosphates are the same as those used to solubilize potassium, so it may be that inducing the solubilization of P also induces that of K. Review the attached paper
Hi Mostafa,
First, the answer of Dr Nelson is what you are looking for.
Regarding glucose, you can use any source of C you want, but you have to know that if you use complexe carbohydrates such as lactose, the bacteria need to activate other other mechanisms in order to break down the molecule and absorb it. Such complex mechanisms are costly in energy. So, glucose is abundant in environment and it is the form that is easy absorbed by bacteria.
Thank you Dr.Lahrach.many authors had mentioned that bacteria faced bad condition like inavailabilty of easily available nutrient like glocose in farms, hence when we determin their potential in lab with easily available nutrient , we are in wrong way........
Dr valero please send English papers.
I knew what you said.but what is the main reason of we add tricalcium phosphate in alekxandrov media?
Dear collegue Mostafa,
It is known that bacteria have the capacity to adapt and they are evolved with time. That's why you can find them into different Earth biotopes characterized by extreme conditions (nutrient starvation, polluted environments, thermal springs,...). When you work on microbes in the lab, in addition of what you are seeking for in your research project, you add another part of phenotypic identification by which you determine the ability of your isolates to grow up with different C or N,... sources, in impoverished media or to resist to harm conditions (HM, HAP, Temperature,...).
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