Re: Quick question about the cecum

Cellulose is processed to a limited extent in the human gut by bacteria.  
The main limitation to this processing is probably retention time.  The 
purpose of the caeca of herbivorous mammals is to hold the food for a 
longer period than would be possible in a simple tubular gut.

The human caeca, known as the appendix, is very small, and I don't know 
whether it is possible for food to enter it.  If food did enter the human 
caeca, then it would be acted on by bacteria just as would happen in the 
gut.  

The passage of food through the caeca of a herbivorous mammal and the 
maintenance of the ecosystem of micro-organisms which break down large 
quantities of cellulose are complex processes which would require a long 
period of evolution to re-create in humans.  I doubt that they could be 
created by short-term genetic manipulation.