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Hi,
I'm a student currently doing my Final Year Project and I needed help for biochemical tests on detecting the presence of Lactobacillus from a sample.
My project involves isolating the bacterias from a sample (fermented beverage) and the aim is to find/ detect the presence of Lactobacillus in it by doing biochemical tests, and molecular methods.
One of the tests is by using Bile salts test to detect the probiotic properties of the colonies that was isolated ( colonies that are picked are rod shaped and gram positive).
My question : When I prepared 0.4% of bile salt solution in MRS broth and distributed to 19 bijou bottles for 19 samples and I autoclaved it after that. Somehow, after autoclave, the solution turns out to have white precipitate in each of the bottles (the bottles are clean and washed) instead of how it was originally in cloudy form. Is it normal for it to be precipitated like that after autoclave? The solutions have to be autoclaved since my work involves bacteria it is to avoid any possible contamination. I was thinking of autoclaving the MRS broth first then add the bile salts later. Is it wise?
After inoculating the bacteria into the bottle with bile solution, the cultures are let to grow and readings are taken after 6hours and 24hours using the UV-Vis spectrophotometer. Since the precipitates present after autoclaving, I fear that it might interfere with the readings.
Hope that you could help. Thank you =)
