Hi to all,
I'm wondering if glucose polymers such cyclodextrins, glycogen and more complex polymers, are metabolized by E.Coli.
Thank you
Hello Antonio,
At least glycogen is metabolized by E. coli. You can see an example here. http://jb.asm.org/content/187/4/1465.short
Also, its highly possible that E. coli is capable of metabolize such polymers since it has a broad metabolism capacity!
Best regards
I think Antonio is asking about the use of extracellular glycogen, rather than the catabolism of intracellular glycogen stores.
As far as I know, E. coli can use short maltodextrins, which are imported via the LamB maltoporin. Using extracellular glycogen and other complex glucose polymers, however, would require the secretion of glycosidases.
ok, than you to all,
@Alejandro is this release in the culture media of glycosidases physiological?
Sorry, I did not explain myself too well. Usually the LamB maltoporin is used for importing maltose and maltooligosaccharides (up to 6 glucose monomers) into the periplasm, where they are further hydrolyzed by the periplasmic MalS alfa-amylase. There should be some leakage of MalS into the culture medium (to an extent that depends on exact culture conditions), and IF MalS can use glycogen as a substrate then yes, I would expect E. coli to exhibit detectable growth on glycogen and, perhaps, cyclodextrins.
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