Read this and answer the question. If the question is unanswerable, say "unanswerable".

Little is known about the bacteria that degrade cellulose. Symbiotic bacteria in Xylophaga may play a role in the degradation of sunken wood; while bacteria such as Alphaproteobacteria, Flavobacteria, Actinobacteria, Clostridia, and Bacteroidetes have been detected in wood submerged over a year.

What component of wood is degraded by bacteria that scientists are still trying to learn about?
cellulose