Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Gelatine Agar
Name: Allison 
Status: Student
Grade:  K-3
Location: NE
Country: United States
Date: January 2006

Can Knox Unflavored Gelatine be substituted for Agar in a petri dish in order to grow bacteria for our science project?

No...the reason sea weed derived agar is used is because very few bacteria can use it as a food source and so it wont be digested. This is not the case with gelatin.


Gelatin will work but some bacteria secrete proteases that will hydrolyze or digest the gelatin. The reslt will be holes in the gellatin where a bacterial colony is growing.

Ron Baker, Ph.D.

It has to have nutrients as well as just gelatin. All living things need a source of carbon and of protein. There are recipes on line for making agar substitutes.


Click here to return to the Molecular Biology Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (, or at Argonne's Educational Programs

Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory