I want to use this substrate to determine cellulose enzyme on petri plates but I've read about low viscosity CMC that "long periods of heating CMC solutions at high temperatures (autoclaving) will degrade the product and permanently reduce viscosity. CMC is therefore very difficult to sterilize. γ-Irradiation, like heating, will degrade CMC. High viscosity CMC is more adversely affected by autoclaving and irradiation than is low viscosity CMC. Filtering CMC solutions tends to leave a gel behind because the material is fibrous, so solutions cannot be sterile filtered."
So, what is the most recommended CMC to determine this activity? Any CMC could be autoclaved? There are a lot of publications about this method with red Congo but nobody says how to sterilise CMC o wich viscosity grade they use.
Thanks beforehand.
Tatiana.
Hi Tatiana, Did you ever receive an answer to this question? I know that γ-radiation changes CMC's viscosity, but am unaware about heat (but you say above that heat changes viscosity too).
I have not tried autoclaving CMC, but given that autoclaving is still a 'themral' process (albeit less heat required heat than compared to dry-heat sterilization), not sure this be suitable... let alone the presence of steam that could change viscosity too.
Of course, given that CMC is hydroscopic, I suspect it might absorb autoclave steam and change state (become a 'brick' or gooey?).
Since you asked this question a year ago, did you try this yet? If so, what did you observe if you don't mind sharing? I'm curious as to what you observed.
Mike
Hi Tatiana,
Autoclaving will reduce the viscosity of CMC. It was mentioned in the link below. Moreover, my personal experience with CMC confirm this point. So, dissolve the CMC in PBS and store it at 4C.
http://101.200.202.226/files/prod/manuals/201209/17/21708001.pdf
Shahin.
Hi,
I did according to this article. We observed the clear zone around the colony growth.
Article Isolation, Identification, and Characterization of a Cellulo...
Yes, l did it. Otherwise, i couldn’t add the substract. I checked the halo.
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