Ethanol is produced from biomass mostly via a fermentation process using glucose derived from sugars (sugar cane, sugar beet and molasses), starch (corn, wheat, grains) or cellulose (forest products) as raw materials. In this form, it is renewable.  Synthetic ethanol can also be produced from non-renewable sources like coal and gas.

Glucose sources

In Australia, ethanol is made from waste products as sugar cane, the waste from starch production, and red sorghum. This means that ethanol production does not interfere with food production at all. Innovations in ethanol continue with the development of other feedstocks, such as algae, cellulosic biomass, trees and grasses.

From a chemical viewpoint conventional ethanol is manufactured via a process where glucose is transformed by yeast into ethanol called fermentation.

fermentation

In this process the feedstock is first converted into glucose.  In the case of sugar this is quite straightforward as the sugar is simply dissolved in water.  Starch however requires pre-processing where the starch is transformed into glucose through a process call liquefaction and saccharification.  This process through the addition of enzymes frees the glucose bound in the starch and makes it available for fermenting into alcohol.

Production process

Advanced biofuels are those that are made from biomass feedstock that does not compete with food.  Such feedstocks include timber, algae, grasses and agricultural residues.

Advanced biofuels are a new area of development which we believe will add value to many agricultural businesses into the future by adding value to waste streams or processing of new biomass streams such as algae.

There are various pathways for developing these biofuels which are now being produced at commercial scale.

cellulosic etoh

The creation of ethanol via fermentation separates the base glucose molecules into both ethanol and carbon dioxide molecules. An advantage of using ethanol as fuel is that it is truly renewable over its entire lifecycle. As the image below demonstrates, ethanol begins its life as carbon stored in biomass; this is converted to ethanol, which is burnt as fuel that emits water and carbon dioxide. Photosynthesis converts the carbon back into biomass, to be used in the next cycle of ethanol production.

EtOH Virtuous Cycle