Cellulosic ethanol

Cellulosic Ethanol
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1. Cellulosic Ethanol Jonathan Boyd

2. Introduction Ethanol is derived from a wide variety of plant materials Two main sources today are corn starch and sugarcane Cellulose is the material that gives the plant its structure Cellulose can not be used for food or feed Recent advances in technology make it a more viable option

3. What is Cellulose? General term used to describe hemicellulose and cellulose Comes from stalks, stems, and leaves of plants Makes up 60-90% of terrestrial biomass Can come from many sources including switch grass, prairie grass, woody crops, and residential and forestry remains

4. Easiest material to make ethanol? Sugarcane is the simplest where yeast digests simple sugars and converts them into ethanol In corn starch enzymes are needed to break down long glucose chains so that the yeast can digest them Cellulose needs even more work to break down tightly held glucose chains which are packed quite differently

5. How is cellulosic ethanol made? Two main steps: pretreatment and fermentation Pretreatment is used to break down the cellulose and hemicellulose Done with a physical step and chemical step and ending with hydrolysis Fermentation is where the yeast digests the sugars and produces ethanol just as you would with any other material

6. What makes cellulosic ethanol difficult? Trying to take the structure of the plant strip it down and break it into small glucose chains The glucose chains are tightly packed to help protect from disease Pretreatment is currently the most cost intensive part of production Scientists are looking for ways to reduce cost and for enzymes that will work more effectively

7. Advantages to cellulosic ethanol Cellulose is very abundant It is not used as food or feed Significantly improves GHG emissions Depends on the composition of ethanol Berkely study estimates a 90% reduction in comparison to petroleum based fuels

8. Project Liberty First commercial production cellulosic ethanol plant located in Emmetsburg, Iowa Started production September 3, 2014 Uses corn stover as the cellulosic material (cobs, leaves, husks, upper stalks) Estimate 20-25 million gallons of ethanol every year

9. Consolidated Bioprocessing (CBP) Mascoma is the company leading the way in CBP Developed specially formulated yeasts that also have necessary enzymes to break down the sugars Their yeasts can also break down xylose which means better yield Using 11 enzymes allows them to achieve 90% hydrolysis yield

10. Cellic CTec3 Enzyme produced by Novozymes Aids in the process of breaking down cellulose and hemicellulose Works 1.5 times better than the previous CTec2 Allows you to use 1/5 the amount compared to competitors

11. Conclusion These advances in technology have greatly helped make it a more viable option Ethanol is something people are already used to and something current vehicles will run off of Only time will tell which technology becomes most prevalent