Antibacterial Properties of Pomegranate in E. coli

[hlambo.4]

Hi,

I am going to be doing an experiment where I will try to identify which acids found in pomegranate have the most antibacterial power. The acids I will be using are 4% ellagic acid and 0.3% gallic acid (since those are the concentrations found in the fruit). I was wondering if it would be better to use an embedded or antiseptic disk method to test for antibacterial activity.

Also, ISEF requires me to explain the safety measures that will be taken regarding the chemicals I will be using and how they will be disposed of. However, I was looking at the MSDS for these acids and they aren't very specific regarding what to do.

Section 13: Disposal Considerations
Waste Disposal:
Waste must be disposed of in accordance with federal, state and local environmental control regulations.
http://www.sciencelab.com/msds.php?msdsId=9923907

In addition, the company that sells gallic acid sells three different types: anhydrous, crystal reagent, and purified. Any suggestions as to which one I should order?

Thanks!
Harrison

[deleted-71884]

Hi,

At those concentrations, there is no way that these chemicals are harmful and/or dangerous to the environment. Acids are only to be treated carefully and disposed of using government procedures if they are highly corrosive (pH of less than 2 or greater than 12). So you can throw it down the sink, as long as the acid is constituted in water and not any other solvent. However, if you are unsure about what to do with those chemicals, you can always call the Environmental Protection Agency regarding your question.

The anhydrous crystal would likely be the best option as that will be most accurate when making your solutions. If you are also unsure about that, you can always call the company for guidance.

Hope that helps!

-Sam

[hlambo.4]

Ok Thanks! That helps me out a lot.
Also, do you have any suggestions regarding whether or not I should incorporate the solutions into the agar or use the antiseptic disc method?

[deleted-71884]

Hi hlambo.4,

You should not put the acids into the agar. Bacteria do not grow into the agar. They grow on top of it, so putting the acid into the agar won't do anything to the bacteria. Instead, spread a small amount of the agar on top of the agar plate once the agar has dried. Then add the bacteria once the acids have dried on the top of the plate.

Also make sure the water you use to make your solutions are sterile and clean. There is nothing worse than having fungus growing on your plates or discovering later than extraneous ions in the water were killing the bacteria instead.

Hope that helps!

-Sam

[mbadtke]

hlambo,
I agree with Sam that you would not want to put the acids into the agar. However, trying to distribute them on the surface might lead to uneven coverage on your plates. I would suggest using discs made of filter paper, soaking your acids into several discs and then observing how large the zone of inhibition is around the disc. The problem with covering the entire plate with your acids is that your desired readout will be a negative result (no growth). Using the discs will allow you to see that the bacteria will grow on the plates, and the inhibition is only from the acids.

Matt Badtke

[hlambo.4]

^^ Thanks for the advice! ^^

Also, I have another question regarding buying ellagic acid and gallic acid. I recently ordered these two products from "sciencelab.com". After looking up reviews of the company, people said that they weren't reliable. I was wondering if anyone knows if this is true. Should I try to cancel my order and purchase the acids from "sigmaaldrich.com" instead?

Thanks!

[hlambo.4]

Hi again,

I will soon order live E. coli K12 from the Carolina Biological Supply Company.
http://www.carolina.com/product/escheri ... estMatches

I was wondering if anybody knows how I am supposed to keep the bacteria alive until I need them for the experiment?

Thanks!

[deleted-71536]

Hi there,

When you order live bacteria from Carolina, it will usually arrive in what is called a bacterial "stab." Typically, the bacteria can live in this culture for several weeks. Your culture will come with instructions, so be sure to read them so that you know exactly what to do to keep the bacteria alive until your experiment.

Good luck!
Heather