BIOREFINING:
WHERE THE PARTS ARE MORE THAN THE WHOLE

by Brian Doidge, OCPA General Manager

Refining means breaking down a raw material into its component parts so that the attributes of these components can be better utilized. Petroleum refineries "fractionate" or break apart the long-chain crude petroleum hydrocarbon molecule into gases, fuels, chemicals, waxes and asphalts using heat and pressure. Biorefining is essentially the same concept of breaking apart the whole into its constituent parts but begins with biological raw materials such as plants rather than non-renewable raw materials such as petroleum. In both processes, the common end goal is to access and utilize the energy in the raw material (in both cases originating from sunlight) that has been stored in the form of carbon: hydrocarbons in the case of petroleum; carbohydrates in the case of plants.

There's more to corn than meets the eye, especially in processing. Corn biorefining processes include abrasion (grinding), chemical reactions (such as hydrolysis), fermentation, filtration and distillation to extract components. An animal is a walking biorefinery breaking down the corn kernel by chewing and grinding, adding acids in the stomach for digestion (and in the case of ruminants, fermentation in additional stomachs), filtration and separation into protein, energy, fat, fibre and gases. Humans cannot digest raw corn kernels well (and we are limited to only one stomach), so we have developed mechanical and chemical processes to break apart the kernel prior to ingestion.

Traditional corn dry milling grinds apart the kernel mechanically into its most basic components: endosperm (starch), bran, and sometimes the germ is separated as well. Traditional corn wet milling chemically separates the germ, starch, gluten, and fibre. However, the corn kernel is a perfect example of the fact that sometimes the individual parts are more valuable than the whole. Increasingly sophisticated biorefining technology is capable of extracting a seemingly endless array of high-value products. For example, corn contains 14 unique amino acids, four pentose sugars, among many other components not found or easily accessed in other plant sources. The trick is to access these components economically and efficiently.

A Minneapolis-based company, Biorefining, Inc., has developed two proprietary processes for converting residual corn plant material into value-added products:

• Its "Biomilling Process" is a pre-fermentation technology that replaces the front-end dry-milling process now used in most corn ethanol plants. This more efficient first fractionation of the corn kernel allows an ethanol plant to increase the number and profitability of its co-products including food-grade corn oil, corn gluten meal, dried fiber feed, and yeast cream. The process also increases per-bushel ethanol yields and reduces overall energy consumption.
• Its "Biorefining Process" converts residual plant matter into value-added products, mainly carbohydrates or sugars, which are then further processed into pharmaceutical, nutraceutical, and functional foods. Using this process, distillers grains can be used to produce such valuable extracts as:
• D-Xylose, a low-calorie sweetener and fluoride replacement
• L-Arabinose, used in disease-fighting medications
• D-Galactose, a low-calorie sweetener used in soft drinks and snack bars
• Galacturonic acid, a nutrient for functional foods and a replacement for phosphates in detergents.

One of the concerns emerging with the enormous expansion of ethanol production in the U.S. is the growing mountain of distillers grains generated as a co-product in corn ethanol processing. Although a valuable feed ingredient, especially for ruminants that can utilize the by-pass proteins, processes such as "Biorefining" add further value by extracting additional products from the distillers grains. The first application of this "Biorefining Process" is a joint venture building a biorefinery adjacent to the 30 million gallon per year (112 m litres) ACE Ethanol, LLC, ethanol plant in Stanley, Wisconsin to be completed in the fall of 2004. ACE Biorefining, LLC, will convert 20,000 tons of wet distillers grains per year from the ethanol plant into starch, cellulose, protein, corn oil, D-Xylose, L-Arabinase, D-Galactose, and Galacturonic acid.

The U.S. is making enormous strides in corn-based biorefining, driven by the desire to free itself from its strangulating dependence on imported petroleum. It is therefore not coincidence that corn-based ethanol plants, already producing fuels to replace petroleum, are emerging as the most likely corn-based biorefineries of the future. And that future is very close at hand.

Cargill is developing a new bio-based platform technology to produce products based on 3-hydroxyropionic acid (3-HP) produced from the fermentation of carbohydrates. Cargill-Dow, in partnership with Shell Global Solutions and Ottawa-based logen, is developing a pilot-scale demonstration lignocellulosic biorefinery project to convert wheat straw and corn stover into sugars and chemicals such as lactic acid and ethanol. logen is searching for sites to locate the pilot plant and is looking especially in Manitoba and Saskatchewan.

In September, 2003, the National Corn-to-Ethanol Research Pilot Plant (NCERPP) opened in Edwardsville, Indiana. Sponsored by the Agricultural Research Service of the United States Department of Agriculture in conjunction with the Illinois Corn Growers' Association, the State of Illinois, and Southern Illinois University in Edwardsville, the NCERPP is a research center for enhancing ethanol production technology, processes, and possibilities. One project is to convert lower-value corn fiber into higher-value chemicals and oils through further biorefining. Another project involves Monsanto who is using the NCERPP to develop and test corn hybrids that are high in fermentable starch content thus producing more ethanol per bushel. Monsanto has identified "High Fermentable Corn" (HFC) hybrids that enhance ethanol production in the dry grind ethanol process. In fact, in the summer of 2003 in Ontario, Monsanto/Dekalb joined Cargill and Commercial Alcohols Inc. in a project to produce sufficient corn from specific HFC hybrids for a month's processing (January 2004) at CAI's Chatham, Ontario ethanol plant. A premium was paid to participating producers who grew these HFC hybrids under contract with Cargill.

In October, 2003, DuPont and the U.S. Department of Energy's National Renewable Energy Eaboratory (NREE) launched a US$7.7 million Cooperative Research and Development Agreement aimed at developing, building, and testing a biorefinery pilot process. The initiative will develop the first fully integrated pilot process making a range of products, fuels, and chemicals from the entire corn plant. Purified sugars from the corn kernel will be the primary source of value-added chemicals, while the remainder of the corn plant (corn "stover") will be converted into fuel-grade ethanol and electrical power. This initiative is part of a larger US$38 million DuPont-led consortium known as the Integrated Corn-Based Bioproducts Refinery (ICBR) project which includes DuPont, NREE, Diversa Corporation, Michigan State University, and Deere & Co.

A press release says, "One of those value-added chemicals could be 1,3 propanediol (PDO), the key building block for DuPont Sonora - the company's newest polymer platform - which can be used in applications such as textile apparel, carpeting, and packaging. Through metabolic engineering, DuPont recently developed a fermentation-based process as the basis for the manufacturing of Bio-PDO. This process earned the U.S. Environmental Protection Agency's Presidential Green Chemistry award earlier this year."

The bottom line is that we are witnessing a bioeconomy transformation from an economy essentially dependent on fossil energy to one far more reliant on biofuels, biopower, biobased products and renewable energy. Corn will play a pivotal roll in that transformation because of its unique molecular starch composition and structure, ready accessibility, efficiency in industrialized processing, and volume availability. The question, as always, will be how to ensure that corn producers reap their share of the benefits in this new corn biorefining economy where the parts are worth more than the whole?