[Peter]

The pre-treatment method depends on the specific crop being digested. Not all lignocellulose can be grouped together.

Grasses such as Naiper grass and certain cover crops may only need chopping,

Wheat straw is not very digestible but the digestibility can be improved with mechanical treatments,

Wood in any form has too much lignin to digest anaerobically and requires complex thermal and chemical treatments to extract a digestible form of cellulose.

Do you have a specific feedstock in mind?