Besides cellulose , there are hemicellulose and lignin .

除了纤维素，还有半纤维素和木质素。

Trees containing less lignin and more cellulose would both grow faster and also produce more ethanol .

含低木质素高钎维的树木能够在既速长的同时又多产乙醇。

Polypyrroles are not as cheap as lignin , but compared with metals they are not expensive .

聚吡咯虽不像木质素那么便宜，但和金属比起来还是比较经济的。

Biofuels from cellulose or even lignin can be derived from inedible plant material and wood rather than food crops .

来自纤维素和木质素的生物燃料可以从非食用植物材料和木料中得到，可以不用粮食作物。

Lignin , one of the two main components of wood , can be modified to do just that .

木质素是木头的两大主要成分之一，经改良后它可以做到这一点。