The fuel ethanol and distillers grains industry may appear to always be the same, but has actually changed over the past several years—more so than most people realize. Our industry sustainably meets the growing needs for food, feed, fiber and fuel for our society as well as the rest of the world. Unfortunately, the public still hasn’t really understood our message, and many perceive our industry as a problem, not an opportunity. We have a lot of work to do to market ourselves, our products, and our benefits to society.

Two key areas will have a profound influence on the long term sustainability of the industry. One thing we need to do is improve processing efficiencies, including resources consumed—energy and water—as well as conversion efficiencies and the optimization of chemicals and processing aids. Online, real-time data acquisition and control systems, coupled with statistical process control and quality improvement programs will help with this. Many plants are making considerable progress in these areas, and every year report tremendous reductions in required resources.

Many in the industry also have begun to realize that they produce more than fuel. As a result, numerous plants now produce high quality coproducts, with very low variability, which is what livestock customers want. Some plants, however, still need to improve their quality control—nutrient level fluctuations and flowability problems are still prevalent, unfortunately. 

The corn ethanol industry definitely has a key role to play in that transition towards increasing volumes of advanced biofuels, as called for in the renewable fuels standard. To move toward true biorefining, though, we must consider fractionation and process integration.    

Fractionation offers many exciting, and still untapped, opportunities to diversify our product and profit portfolios. In terms of pre-fermentation fractionation, there are several approaches to separating the germ and bran from the endosperm. For post-fermentation fractionation, there are growing opportunities as well, including size classification, air aspiration, and filtration/membrane systems. We’ve seen an exponential growth in the use of centrifuges to remove oil from stillage to be used for biodiesel production. All of these fractionation methods will, of course, lead to unique coproduct streams, beyond traditional DDGS.

But the exciting opportunities have really just begun. Fractionation from the corn kernel and from coproducts will allow us to separate the higher-value components from the mid- and low-value materials. Concentrated proteins, for example, can be used for high-value applications such as aquafeeds, pet foods, human foods, bioplastics or other industrial purposes. In its concentrated form, zein protein has many unique attributes and applications in films and plastics. There are also opportunities to extract nutraceuticals, such as phytosterols, or other organic molecules for novel uses.

Traditional DDGS and WDGs will continue to play key roles as livestock feed, but new types of DDGS could be produced using mid-value components from fractionation systems. The lower-value materials, such as the fiber, work extremely well as low-cost fillers in biocomposites. This is a very exciting opportunity, because other fillers, such as wood flour, cost up to $10 per pound, whereas DDGS fiber typically costs less than a few cents per pound—an opportunity to increase the value of coproducts more than 200 times. Equally exciting is pretreating the fiber and fermenting it into additional fuel ethanol, which many see as a natural step into advanced biofuels production, since the cellulosic biomass is already available for use at the ethanol plant. Other possibilities include using the fiber and other low-value components in thermochemical conversion (such as pyrolysis and gasification) or anaerobic digestion systems to offset fossil fuels used for power and steam. Initial studies have been promising, and technology providers are beginning to take notice.

Integrating these new processes into new and existing ethanol plants, and then marketing these novel fractionated products will move our industry into true biorefining and will lead the way to next-generation biofuels. All of this will take effort, but in the long term will reap considerable benefits and profits. Integrating these new systems, and making current operations more efficient, will improve the overall life-cycle assessment and sustainability of our industry.  These are key steps to improving the public’s understanding of our industry.  But we also need to actively market ourselves and our advancements.

Author: Kurt A. Rosentrater, Ph.D.
Lead Scientist, Agricultural and Bioprocess Engineer
USDA Agricultural Research Service
(605) 693-5248
kurt.rosentrater@ars.usda.gov