Cellulosic biomass

DSEC's commitment on the construction of Bioethanol plants is based on a very specialized technical knowledge of the Ethanol production processes; in this article you will find a more detailed understanding about the process of Cellulosic biomass.

Cellulosic biomass is the structural portion of plants and includes agricultural (e.g. Corn Stover, which is the entire above-ground portion of the corn plant, excluding the grain) and forestry (e.g. sawdust) residues, major fractions of municipal solid waste (waste paper and yard waste), and herbaceous (e.g. switch grass) and woody (e.g. poplar) crops grown as energy resources. Although distinctive in outward appearance, these materials all comprise about 40-50 % cellulose and 20-30 % hemicelluloses, with lesser amounts of lignin and other compounds, such as sugars, oils and minerals.

Cellulose is a polymer of cellobiose (glucose-glucose) sugar molecules that are physically linked together in a crystalline structure to provide structural support for plants. Within these micro fibrils cellulose is found in two forms, namely amorphous and crystalline. The crystalline form of cellulose is particularly difficult to degrade and typically makes up the core of a lignocellulosic microfibril.

Bio-Ethanol Cellulosic biomass

Hemicellulose is also made up of sugars covalently joined together in long chains (short, highly branched), but it generally includes five different sugars: arabinose, galactose, glucose, mannose and xylose. In addition, hemicellulose is an amorphous, branched material. Lignin is a phenylpropene compound that can be viewed as a low-sulfur, immature coal. It is a large complex polymer of phenylpropane and methoxy groups, a non carbohydrate polyphenolic substance that encrusts the cell walls and cements the cells together. It is degradable by only few organisms, into higher value products such as organic acids, phenols and vanillin.

Upstream process requirements:

  • Size reduction / Milling
  • Pre- treatment
  • Hydrolysis
  • C6 - Fermentation with standard yeast or C5/C6 - Fermentation with GMO