Biomass fermentation involves breaking down glucose inside organic material to produce ethanol. The end goal is the production of ethanol with sufficient alcohol concentration to fuel automobiles, while also finding uses for the solid byproducts. Biomass fermentation is one strategy designed to power vehicles without using fossil fuels.
Fermentation involves changing the glucose or carbohydrate within a plant into an acid or alcohol. In the case of biomass fermentation, technicians add bacteria or yeast to the biomass, allowing them to turn the sugars into carbon dioxide and ethanol. They then distill the ethanol, dehydrating it to achieve a greater concentration, as the purity requirements for vehicle fuel are high. Biomass fermentation also creates solid byproducts that are useful in the production of cattle feed.
For the production of ethanol, the most productive biomass has a high sugar content. Corn, sweet potatoes and sugarcane are some of the most commonly used plants, although wheat, rice, barley, oats and even agricultural wastes can be used. Agricultural wastes, though,contain lignin, which does not ferment but is useful in producing heat and electricity. The use of biomass with lignin takes longer because of the increased complexity of converting it into sugars that are fermentable.