Cander Eti, a Sucker Mouth Armoured Catfish

The cander eti, they are called, a sucker mouth armoured catfish. They scrape wood with their teeth to get organic material off it. It has special spoon shaped teeth as well. This is the weird thing, we can't digest wood. But i think the reason for this is that we don't have organisms in our gut which produce the enzyme cellulas rigts a Wood pulpi cellulose. And if you have the ensime cellulas, you can digest it. You'd be able to do it just like a probiotic. So we're eating a lot more wood than we realize. Is there any species of tree that we do eat? I now, sinot