Cracking The Kernel For Higher Value Products

Researchers hope phytate replicates the corn oil extraction success story, but the history of zein shows it can be a slow and difficult road to success.
By Susanne Retka Schill | June 10, 2015

Diversification of coproducts is increasingly important to the ethanol industry, as the widespread adoption of corn oil extraction has demonstrated so well. Penetrating markets with a new coproduct is no easy task, though. Zein, for instance, has shown promise for decades, but has gained little traction. Now, a team from the University of Minnesota is working on a new coproduct—phytate. In addition to providing a new coproduct with multiple uses, the remaining distillers grains could be considered enhanced with distinct market advantages.

Plants hold on to phosphorus in their seeds in the form of phytate, explains Doug Tiffany, a University of Minnesota extension economist. “It’s useful. If you think about the grain, it’s the source of phosphorus for germination.” However, it’s not always so useful in feed, he continues. “There’s little problem for cattle to utilize the phosphorus, but the poor digestibility of phytate is an issue with monogastrics. That’s what leads to overfeeding and more of it ends up in manure.” For Southeast poultry producers or North Carolina pork producers, phosphorus leaching out of the soils is a growing environmental issue.

There would be other benefits for low-phosphorus distillers besides reducing an environmental concern, Tiffany says. “Lower phytate levels make other nutrients more available and useful to the animal, such as the protein and the vitamins.” The new DDGS would be attractive in feed rations for monogastrics like poultry and swine, as well as for fish, a new and potentially big market for distillers. 

A team from the Department of Bioproducts and Biosystems Engineering, led by Professor Bo Hu, has developed a process to extract various forms of phytate from distillers grains. U of M nutritionists Jerry Shurson and Pedro Urriola and economists Tiffany and Won Lee are working on other aspects of the project. With a year of research completed, the team hopes to launch a two-year pilot study, working with cooperating ethanol plants. “It’s nice to have cooperators in the industry offer us guidance on how to make something like this fit into a plant,” Tiffany says. “That integration is key, you don’t want to upset the process.” The goal is to design a bolt-on process that will divert a portion of the whole stillage stream for chemical extraction of phytate. In addition to working out the integration with the ethanol process, the pilot facility will aid in predicting costs and efficiencies and provide more material for further testing.

“A big challenge is to understand the marketing side,” Tiffany continues. The U.S. currently imports phytic acid, a commercial form of phytate, from China and Japan, where it is extracted from the byproducts of rice milling. “They have a lot of experience and they have some high-purity production of phytic acid that goes for pharmaceuticals and different food products,” he explains. Phytic acid is used as a preservative and antioxidant by the food, pharmaceutical and cosmetic industries. One industrial market is as an anticorrosive treatment for metal surfaces. The researchers are now learning more about the different markets, the range of formulations and quality specifications.

Tiffany knows well the challenge of creating a viable new coproduct. He was involved in the research team headed by Pavel Krasutsky at the Natural Resources Research Institute at the University of Minnesota-Duluth, who began researching alternative products from distillers grains in 2004, zein among them. Phytate has been known for some time as well, Tiffany says. “People pick these things up and set them aside and, after a while somebody will start some research and maybe see a new technique and the whole proposition will be much closer.”

Zein Debute
The corn protein extract zein falls into the category of an idea that has been set aside and revisited several times. Discovered in 1821, the first patented process for extraction of zein from corn gluten used ethanol as a solvent. It became commercially available in 1938 and reached a peak production of 7 million kilograms (15 million pounds) per year in 1956, according to a 2009 paper found on the webpage of University of Illinois professor emeritus, Munir Cheryan. “Today there is one known manufacturer of zein in the U.S. and one in Japan. The cost of purified zein is $20 to $70 per kg, depending on the grade and purity. However, this price makes zein an uneconomical material for large industrial uses such as biodegradable plastics, since petroleum-based polymer resins sell for much lower prices (35 to 70 cents per kg),” the paper says.

Cheryan’s team at the University of Illinois Urbana-Champaign developed and patented a zein extraction method which they dubbed COPE, for corn oil and protein extraction. Using membrane technology allowed selective low-energy, low-cost separation of zein and for the recycling of the ethanol solvent “without the substantial evaporation costs that now limit other zein extraction process,” Cheryan’s description reads. Zein has multiple uses. The protein has been the subject in more than 3,400 patents since 1976 and has the potential to become many things such as biodegradable plastic, food and paper coatings, chewing gum base, biodegradable textile fiber, pharmaceutical encapsulation for time release medicines and much more.

In 2006, Prairie Gold Inc. was formed to license the University of Illinois technology. Philip Shane, who worked at the Illinois Corn Marketing Board and the Illinois Corn Growers Association which funded the research, became its president. Prairie Gold, however,  is not the first to attempt to reclaim the zein market. In 2009, Poet LLC announced it had commercialized a patent-pending process to produce zein, which it dubbed Inviz. While some zein has been produced by Poet, full-scale production has yet to take off.

Shane, now director of zein operations and sales for the JV, declined an interview for this article due to Prairie Gold being in the quiet phase of an equity fundraising drive.

Prairie Gold’s project got off to a good start, with a USDA grant to help with development and collaboration with Katzen International Inc. to work on integrating the COPE technology in a pilot plant. By the fall of 2009, the pilot facility was under construction in Rochelle, Illinois, next to Illinois River Energy (now under new ownership and renamed CHS Rochelle).

The timing was unfortunate, but unlike many projects that expired in the Great Recession, Prairie Gold rose again. In October 2013, the company announced a joint venture with Big River Resources LLC. Big River Prairie Gold LLC began construction a year later on a zein production facility near Galva, Illinois, on the site of one of Big River’s 110 MMgy ethanol plants.

Nearing completion, the 15,000 square foot facility will produce a high-quality, food- and pharmaceutical-grade zein protein. The first-of-its-kind plant will process about 600,000 bushels of corn per year, extracting zein at the front end of the plant after the corn is ground, and recycling the ethanol solvent into the plant while returning the starch component to the ethanol process. In early May, the plant was on track to come online this summer and begin its shakedown and start-up period.

Author: Susanne Retka Schill
Senior Editor, Ethanol Producer Magazine
[email protected]