Name: Vanessa
Status: student
Grade: 9-12
Location: CA
Country: USA
Date: Fall 2011
Question:
Hi, I'm doing an experiment that involves the effect garlic extract on the growth of E. coli bacteria in nutrient agar. How should I sterilize that garlic extract if the main anti-bacterial agent within garlic is the unstable compound Allicin?
Replies:
Dear Vanessa,
One way to sterilize small molecules such as allicin is to pass the extracts through filters that have pore sizes of 0.45 micrometers or less that will trap the bacteria but allow the smaller molecules to pass through. You may want to remove large particulate matter by centrifuging the crude extract and then taking the liquid fraction and filter-sterilizing it.
Your experiment will be interesting.
Good luck,
Jim Tokuhisa, Ph.D.
Assistant Professor
Horticulture Department
Virginia Tech
Hi,
Basically, Allisin is transiently formed compound during crushing of garlic. Since you cannot boil/ autoclave it, so to my mind is filter it using smaller pore filters manufactured by Millipore. These are bacterial filter that fit with a syringe. I hope that would do the trick.
Regards
Waseem S Abbasi
Rather than heat sterilization, consider the use of physical exclusion instead. A syringe and sterilizing grade filter should exclude any biotic contaminants. You may want to do a few pilot runs with different pore sizes to see which does the job most satisfactorily.
Dr. Tim Durham
Instructor, Office of Curriculum and Instruction
University Colloquium
Department of Biological Sciences
Florida Gulf Coast University
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