Enzymes can break down wood into sugars for biofuel, but some types of wood are harder to digest than others. Poplar wood is easier to break down than larch wood after being treated with acid. The researchers found that the lignin in larch wood physically blocks enzymes more than in poplar wood. Adding a protein called BSA helps enzymes break down poplar wood better. The way lignin is spread out in the wood affects how well enzymes can work on it. This study helps us understand how to improve the process of turning wood into biofuel.