General Biomass Cellulosic Ethanol Page

What is cellulosic technology?
Cellulosic technology is a technology which can help fight global warming. Cellulosic technologies encompass all the aspects of making biofuels and renewable plastics from cellulosic biomass. Such technologies include enzyme manufacture, cellulose and hemicellulose hydrolysis, biomass pretreatment, and lignin combustion or conversion. Two major types of cellulosic ethanol technology are 1) gasification of biomass to synthesis gas and resynthesis of larger molecules like ethanol, and 2) enzymatic hydrolysis of cellulose and hemicellulose to component sugars, followed by fermentation to ethanol or other bioproducts. Gasification methods have the advantage of being fast and relatively less sensitive to feedstock type, but the disadvantage of destroying useful structure like the glucose molecule. Enzymatic methods are slower, but produce glucose, which is the metabolic substrate of choice for producing ethanol, butanol, renewable diesel, renewable jet fuel, and a wide variety of useful organic acids as industrial feedstocks for plastics and biobased chemicals and solvents.

Cellulosic ethanol made from biomass will produce smaller amounts of greenhouse gases than corn ethanol, and far less than the gasoline it will replace. This greenhouse reduction potential can be estimated by Life Cycle Analysis (LCA), used by numerous groups to evaluate the net energy balance and carbon balance of ethanol from corn and cellulosic biomass. The two best examples of this analysis are (1) from Kammen's lab at Berkeley - Farrell et al. (2006) Ethanol Can Contribute to Energy and Environmental Goals and (2) from Michael Wang (2005) at Argonne National Lab in Chicago: Updated Energy and Greenhouse Gas Emission Results of Fuel Ethanol.

With continued technology improvements, cellulosic ethanol should become cheaper than gasoline. Because it is locally made, it reduces the transfer of wealth caused by oil imports. E85 Hybrids can drastically reduce gasoline consumption.

What is cellulosic ethanol?
Cellulosic ethanol is fuel ethanol made from glucose, a 6-carbon sugar derived from the cellulose in biomass. Cellulosic ethanol is a substitute for gasoline. It is chemically identical to ethanol made from food crops like corn and sugar, but comes from wood, waste paper, and energy crops like poplar and switchgrass. Cellulosic ethanol is more difficult to make, because cellulose is a tough structural material, unlike starch from grains which is easily broken down to glucose sugar.

The primary feedstocks for fuel ethanol today include glucose from corn starch in the U.S., currently producing about 6 billion gallons of corn ethanol per year. Additional corn ethanol plants could push the total to 12 billion gal/year, with the downside of increasing corn prices and encouraging the shift of wheat and soybean acreage to corn. One bushel of corn produces about 2.8 gal ethanol, so 12 billion gal corn ethanol will require about 4.3 billion bu/year, a significant fraction of the U.S. corn crop.

In Brazil, the primary feedstock for fuel ethanol is sucrose (white sugar) from sugar cane, a more efficient source than corn. Standard gasoline in Brazil is about 25% ethanol, and flexfuel vehicles using E85 are popular. Growing large amounts of sugar cane is not an option in the U.S., Canada and Europe because of the tropical climate required.

Cellulosic ethanol can be made from a variety of biomass feedstocks including recycled paper, urban waste paper diverted from municipal solid waste (MSW), energy crops like poplar, willow, and switchgrass, wood waste, and waste streams from pulp and paper mills. Cellulose and hemicellulose are the two carbohydrate components in most biomass, and can be hydrolyzed (split) into their component sugars: glucose and xylose, both of which can be fermented to ethanol, other biofuels like butanol, or lactic acid which can be made into biodegradable or more permanent plastics and fabrics.

Why should we make cellulosic ethanol?
Making ethanol from cellulose lets us tap into a much larger source of sugars, and therefore potentially make much larger amounts of biofuels, tens of billions of gallons or more, without using food crops like corn. Given investment and technology development, it is possible to replace at least 25% of the U.S. gasoline supply with cellulosic biofuels, requiring about 50 billion gallons.

What is cellulose and where does it come from?
Cellulose is a polymer or string of glucose molecules joined together in linear rows. The parallel rows of glucose molecules form a tough crystalline substance which gives wood, paper and cardboard their strength. Cellulose comprises about 40-60% of the material in common forms of biomass, such as wood, paper, switchgrass, and corn stover. Cellulose is probably the most abundant organic molecule on the planet.

The other biomass components are hemicellulose, made from 5-carbon sugars like xylose, and lignin, which is a set of non-sugar molecules acting like a glue to hold the biomass molecules together. The 5-carbon sugars, or pentoses, can also be fermented to ethanol, and the lignin can be burned for energy. Glucose, pentoses and lignin from biomass are currently the only feasible alternatives for large-scale substitution of petroleum hydrocarbons.

E85 vs E10
E10 is a blend of 10% ethanol and 90% gasoline which runs in all standard automobiles without modification. Assuming the U.S. uses 140 billion gal of gasoline per year, it would take 14-21 billion gallons of ethanol to make all U.S. gasoline as E10. Ethanol has about 2/3 the energy content of gasoline per gallon compared to gasoline, but has a higher octane rating, hence the range of values. Wholesale gasoline is purchased as RBOB, a lower octane gasoline to which an octane enhancer like ethanol must be added to make retail gasoline. Previous octane boosters like MTBE and tetraethyl lead have been outlawed due to their environmental toxicity.

E85 is a blend of 85% ethanol and 15% gasoline which runs in flexfuel vehicles, or FFVs. There are about 6 million FFVs in the U.S. and millions more in Brazil and other countries. FFV technology costs about $200 per vehicle and consists of modifications to the fuel injection computer, gas lines, etc., and sometimes a larger gas tank. FFVs allow a driver to fill up with any mixture from straight gasoline to E85, with the automotive system automatically sensing and adjusting the air/fuel mixture appropriately.

Widespread blending and sale of E85 is thus the next stage in wider use of biofuels like cellulosic ethanol, assuming the appropriate ethanol and fuel pumps are in place. To date, the major oil companies have resisted the expansion of E85, since the retail product contains only 15% gasoline made from oil. This creates a large opportunity for vertically integrated cellulosic ethanol companies which would have access to biomass feedstocks, refine the ethanol, blend it as E85, and sell it at retail E85 stations, which could offer snacks and other fuel pumps much like gas stations today. The difference would be that the bulk of the fuel product is renewable, and branding and ownership would reside in new companies.

What is General Biomass Company doing?
General Biomass develops proprietary technology to make large quantities of cellulase enzymes, the protein catalysts which turn cellulose into glucose. It takes about 100 grams of cellulase enzyme proteins to make 1 gallon of cellulosic ethanol. This means that just one billion gallons of fuel ethanol would require 110,000 tons of cellulase enzymes, or about twice the annual production of all industrial enzymes in 1994. General Biomass technology will help fill the need for the large quantities of cellulases necessary to begin replacing gasoline with ethanol in the U.S. and Europe.
General Biomass also offers scientific and technical consulting for cellulosic ethanol, biorefineries, and the production of fuels and chemicals from biomass.