1. The Propionibacterium is best grown in Thioglycollate broth... This broth helps in maintenance of both pH and anaerobiosis. No anaerobic atmosphere is required.....

2. It can also be cultivated in Brucella blood agar enriched with 5% sheep blood, 5 mg/L haemin and 1 mg/L vitamin K1, (Cat No. M 1039, Hi-Media Laboratories Private Limited, Mumbai) BUT IT REQUIRE - ANAEROBIC atmosphere (85% N2, 10% H2, 5% CO2)

The acid production by bacteria inhibe the grow in liquid medium. I think you can use 0.5 g/l de calcium carbonate in the medium ricipe, to neutralize the propionic acid.

The genus Propionibacterium are you working? This genre, perhaps, like low pH, since it acidifies the medium. In any case, you could test the MRS medium (Man Rugosa-Sharp) that I use in my work for lactobacilli harvest.

Yes, I think you both are correct! Its acid production inhibit cell growth. Using a base to neutralize pH or MRS are good alternatives, but I was thinking about changing the organism itself to improve his growth speed.

I've never read anything about it, but I was thinking about adaptive evolution to somehow select fastest organisms... Is it possible at all??

1. The Propionibacterium is best grown in Thioglycollate broth... This broth helps in maintenance of both pH and anaerobiosis. No anaerobic atmosphere is required.....

2. It can also be cultivated in Brucella blood agar enriched with 5% sheep blood, 5 mg/L haemin and 1 mg/L vitamin K1, (Cat No. M 1039, Hi-Media Laboratories Private Limited, Mumbai) BUT IT REQUIRE - ANAEROBIC atmosphere (85% N2, 10% H2, 5% CO2)

To select fasts microorgansims the best way is in continuos culture. You can beging with a low dilution rate (D) and increases it slowly. You must to care about wash out.

Thanks Dr. Murali! I will take this notes and use it with my Propionibacterium.

That is a great idea Dr. Silva! Maybe this way I can select fastest organism and, consequently, improve production.

Thank you all for the help!

Another advise is to care how fast grow. In a culture media or conditions that promote the faster grow the acid production is poor. The higth rate grow is not good for metolites production.

I think all the above comments are true, but my mind accept better to utilize the base to neutralize the acid or ph of the medium

Can we think of using an amino-polymeric resin as sink for the propionic acid produced? It will very gently keep away the acid and give back at the end? I think this principle has not been used so far!

Polyethylene amine? Or any weak basic ionexchange resin?

for adaptive evolution I think i would be better to start series of cultures instead of continuous cultures, and you inoculate from the first in the second and so on till you get a better strain with magnified acid tolerance, however, i still think the ca carbonate idea is more feasible, and the polyethylene amine is also a good challenging, why don't you try it.

ion exchange resin use is unorthodox and worth trying. In chemical industry in some cases good results are achieved , ease in processing the product, no high or low pH that can spoil the molecule, no high temperature anywhere etc.

Pl give a try.

@Md Shahbaz Anwar. we tried to neutral using base(calcium carbonate) but propionic acid production is (very low around 1.23% after 5 days).

I tried by increasing the Caco3 percentage (plating ) and got clear zones but problem is how to conform it is producing propionic acid only (as it produce other acids which react with Caco3 ,and leads to clear zone ) .I am using MRS media

I want to improve the production of propionic acid ...please give any suggestion.

Thank you

MRS media is not a good media por producción metabolites.Please review this link Volume 4, Issue 2, January 2000, Pages 121–128

@ Edelberto Silva can you please send me the link

Soory the article is "Fed-batch propionic acid production by Propionibacterium acidipropionici" Biochemical Engineering Journal 4 (2000) 121–128. It is free.