Saliva helps the mouth to break down the food, but what digests the food is fiber, and stomach acid.

In order to digest food with fiber, you need to have the enzyme cellulase that can break down the bonds between the two cellulose molecules, or have a symbiotic organism that does. Such symbiotic relationship is the case for termites. Inside the intestines of termites, there are small protists known as Trichonymphathat digests wood.

what enzyme digests vegetable oil

How tilapia fish digests crude fat

it digests its food by making it go through its intestines