Biofuels | Biochemical ethanol

For the past two decades, the CanmetENERGY has assisted Canadian firms in making the production of ethanol from biomass a commercial reality. Ethanol can be made from a variety of feedstocks, including sugars, starches, and ligno-cellulose materials, and possibly even algae. Currently, commercial ethanol technologies are based on the conversion of sugars and starches (e.g. corn and wheat grains). However, these first generation technologies are limited by the availability and sustainability of “food” feedstocks. The next, or second, generation of technologies will utilize non-edible and waste biomass streams to produce biofuels.

At present, major breakthroughs are being made in the conversion of ligno-cellulose (from both forest and agriculture operations) into ethanol. The amount of ligno-cellulosic material currently available in Canada could theoretically provide well in excess of 1.4 billion litres, which is the amount of ethanol required to achieve the Canadian government's target of gasoline containing 5% ethanol by 2010. In order to achieve this target, work is needed to further improve the conversion technologies and to reduce the cost of ethanol production.

Conversion Pathways for the Production of Ethanol

Conversion pathways for the production of ethanol involve either a biochemical (fermentation) or thermochemical (gasification) process.

The fermentation process involves pretreatment and then hydrolysis (achieved via enzymes and microbes) of the feedstock, which is usually plant-based. Most plant matter consists of the three key polymers of cellulose, hemi-cellulose, and lignin. Cellulose and hemi-cellulose are carbohydrates that can be broken down into fermentable sugars. Each needs to be processed separately, because their structures and sugar content are different. The goal is to break down the cellulose into its sugars and then convert these to ethanol through a process involving enzymes/fermentation.

The thermochemical conversion pathway to ethanol gasifies feedstocks (from renewable waste materials such as wood waste, crop residues, and organic waste) to produce a syngas. The syngas is then converted to bio-alcohols, which are then separated and purified to produce ethanol, methanol, and other valuable products.

Currently, our focus is on forestry residues such as wood residues and sawdust, and on agricultural feedstocks such as straw and perennial grasses. We are also making great strides in converting municipal wastes. We are proud of our role in moving ethanol-from-waste out of the laboratory and into the marketplace.

To find out more about biochemical ethanol visit our publications section.