Sweet Discovery

BPX technology: redefining the ethanol process.

As the ethanol industry heats up amidst growing demand, increased publicity and booming production, Sioux Falls, S.D.-based POET has found a way to get ahead by keeping its refining process cool: with a raw-starch hydrolysis process known as BPX™.

To understand the importance of patent-pending BPX, it’s necessary to have a basic understanding of the processes involved in ethanol production. In traditional corn-to-ethanol production, the corn is ground and mixed with water, then heated in a jet cooker. The resulting material is liquefied and used in a fermentation process where the starches are converted to sugars, and the sugars to alcohol. BPX streamlines the process, eliminating the cooking and liquefaction steps.

“The three main advantages of BPX are a more efficient process with a better conversion of starch to ethanol, reduced energy costs and superior quality co-products,” says Mark Stowers, Vice President for Research and Development at POET. “With other technological innovations, we actually increase the overall ethanol yield and productivity.”

While the idea behind raw starch ethanol production is not new, a workable process had evaded researchers for years. This made it all the more surprising when Steve Lewis, POET’S Chief Science Officer, discovered the process while researching conventional ethanol production techniques.


The road to the BPX process began with research into methods to optimize the conventional heat-based ethanol process. From 1998 to 2000, researchers at POET were successful in bringing up the gravity, or increasing the solids, in their conventional production process. As researchers increased the solids, they discovered the levels of residual starch in the leftovers of fermentation increased. The POET researchers began looking into ways to convert these leftover starches into sugars, and ultimately ethanol, by running tests using raw starch flour and various enzymes. They eventually discovered a side activity in the enzymes that was achieving raw starch hydrolysis, the conversion of starches to fermentable sugars, without the cooking and liquefaction steps present in the traditional method.

“This was the serendipitous event,” says Lewis. “We discovered that, with a few changes here, we can actually convert raw starch to ethanol in a very efficient manner.”

The enzyme supplier, Denmark’s Novozymes, was told about the findings and asked to reproduce and isolate the side activity the POET researchers, then at Broin, had observed. This new avenue of research was given the code name “Broin Project X,” or BPX, in order to keep the work secret while under development. Attempts to optimize the conventional process continued in concert with research into the new raw starch method, but the focus of the company’s efforts soon shifted.

“At some point, we realized that the raw starch process was out-competing the conventional one,” Lewis says. “We were saving in energy, we had higher yields; it was altogether a much more efficient process. Initially, the raw starch process was just an intellectual curiosity, but as we learned more about its specific advantages, it transitioned from an interesting discovery to an exciting commercial opportunity.”


Trials continued in the lab until May 2003, when the new process was implemented at the POET research facility in Scotland, S.D. In May 2004, the BPX process was commercialized at its first large POET-managed facility, a newly constructed plant in Hudson, S.D. Since then, BPX has been implemented in all of POET’s newly constructed plants, and has been retrofitted in all but two of the company’s conventional facilities.

BPX technology is also a key element in advancing cellulosic ethanol production. It is one of the technologies necessary to develop the integrated grain to ethanol and biomass to ethanol production facility. The technology, Stowers says, is beginning to change the common conception of what it means to be in the ethanol business.

“When you take BPX, it serves as a foundation for technology that allows us to look at an ethanol plant that can produce other things,” he says. BPX is the foundation of the branded Dakota Gold® Dried Distiller’s Grain with Solubles (DDGS) co-product. By eliminating the cooking and liquefaction steps, the BPX process allows for less heat damage resulting in a co-product with higher available nutrients, and improved physical characteristics such as higher density, easier pelleting and enhanced flowability—an important factor in the feed industry.

Adds Lewis, “We’re transforming from an ethanol and feed company to a biorefinery. In theory, anything you can make out of a barrel of oil, you can make out of a kernel of grain, and the advantage of grain, or biomass, is that it is a renewable resource.”

Although the process has been a great success, reducing the net cost of producing a gallon of ethanol, researchers continue to fine-tune and improve their methods. Novozymes has been a willing partner, introducing new enzymes to improve the enzymatic aspect of the process.

Lewis still sees room for improvement. “One of the anomalies is that we have a higher level of residual starch left at the end of fermentation than in the conventional process,” says Lewis. “So the yeast fermentation is a little more efficient, more of the carbohydrate in the corn goes to ethanol and less goes to co-products.”

To assist in researching this effect, POET is collaborating with Iowa State University Professor Jay-lin Jane, based in Ames, Iowa. Jane, a specialist in starch biochemistry and starch structure anatomy, is working with POET to further understand and optimize the BPX process.

“Jay-lin is using her analytical expertise to document the changes in starch that occur during the fermentation,” Lewis says. “She also is using her knowledge of cereal chemistry to research the impact of the corn hybrid on fermentability, trying to get at it from the genetic side.”

This collaboration, Lewis hopes, will lead to even more efficiency and improvement.

“With Jay-lin’s expertise, we will be able to take an objective look at the yields in this process, and we’ll gain insight into how to improve.”




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