IUBio

Cellulases

David Slomczynski boytrytis at peachnet.campus.mci.net
Thu Sep 3 19:12:38 EST 1998


In article <35EF00FA.505FEAE8 at teliamail.dk>, jan bille <jan.bille at teliamail.dk> wrote:
>Hello!
>Does anyone know about hydrolysis of dyed substrates by endocellulases
>?  I have tested AZCL-HEcellulose and RBB-CMcellulose with a
>cellulolytic bacteria. On both substrates I find hydrolysis, but the
>bacteria can not grow on the corresponding undyed substrates.
>Are cellulases other than endocellulases able to hydrolyse dyed
>substrates like AZCL-HEcellulose and RBB-CMcellulose ?
>If I measure endocellulase activity with a dyed substrate I would expect
>my microorganism to grow on the corresponding undyed substrate, or could
>this be an exception ?
>Have you experienced microorganisms which are able to degrade and grow
>on crystalline cellulose, but unable to grow on substrates like
>HEcellulose and CMcellulose ?
>
>Annemette Sørensen
>

A simple answer is YES. Inorder to break down cellulose, both exo-acting and 
endo-acting enzymes are needed. It is the exo-acting that give off glucose and 
cellobiose, while the longer polymer is made accesible by the endo-acting 
enzymes. A better measure of enzyme activity would be CMC viscosity 
measurements. CMC acan react with endo-cellulases, but not exo-cellulases. 
Look up a paper by K.-E. L. Eriksson, et al on the measurement of 
endocellulases. Hope this helps and good luck.

                                David Slomczynski



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