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Lignocellulosic Biomass

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Lignocellulosic biomass is made up of three main components: cellulose, hemicellulose, and lignin.

Cellulose and hemicellulose, like starch, are made up of sugars. Unlike starch, the sugars in cellulose and hemicellulose are difficult to get at. The plant cell walls containing hemicellulose, cellulose, and lignin form an extremely complex structure that is very difficult to break down. There are four main steps to break down the biomass into its sugars: pretreatment, enzymatic hydrolysis, fermentation, and distillation.

The purpose of the overall process is to obtain as much sugar from the biomass as possible—the more sugar, the greater the amount of ethanol produced. The lignin does not contain any sugar, but can be burned to produce heat and electricity.

Lignocellulosic Biomass

Lignocellulose and Its Components
(Image: USDA Agricultural Research Service)