Is corn fiber the next big opportunity for ethanol producers?
This post will be the first rendition of Technical Service Monthly, a Think Bioenergy column dedicated to helping you do two things: (1) ensure your current technologies and solutions are working effectively and (2) identify opportunities to improve in the future.
For decades the corn ethanol industry has taken advantages of opportunities for improvement and optimization. Thirty years ago farmers produced less than 100 bushels of corn per acre; they now grow 160 bushels per acre. Moreover, according to the U.S. Energy Information Administration (IEA), the ethanol produced per bushel of corn has increased by over one-fourth of a gallon since 1982. Finally, 90% of US starch-based ethanol production has shifted from wet-milling to more energy-efficient dry-milling, meaning that less energy is used in the production process.
These innovations have made a bit of biofuel history and serve as a prelude to future developments.
Is the next big opportunity corn fiber?
You already know that there is fiber in corn. You might not know that there is starch bound within the fiber. Traditionally, the “fiber-bound” starch represented a lost opportunity because it’s inaccessible to traditional glucoamylases – enzymes that separate sugars from starch. Thus, for the majority of corn ethanol plants, most of this trapped starch moved untouched through production.
Looking to convert more of the corn kernel into ethanol, the industry innovated. Less than two years ago, a fiber-degrading glucoamylase hit the market, allowing corn ethanol producers to produce more ethanol out of the same bushels of corn. The technology degrades the kernel fiber, releasing the additional pool of bound starch and ultimately resulting in a higher ethanol yield.
Corn fiber itself is a cellulosic substrate similar in many respects to biomass: It has the same basic components as biomass but in different ratios. One major compositional difference of corn fiber is that it doesn’t have the lignin found in biomass, which actually makes it easier to access by enzymes. In fact, a very mild pretreatment system and a low enzyme dose are sufficient to ready the corn fiber for conversion into sugar. Better yet, it’s a captive feedstock in the sense that it’s already being brought to plants. Therefore, it’s very low-hanging fruit for the production of cellulosic ethanol.
Let’s say all of the approximately 200 ethanol plants in the United States adopted a cellulosic ethanol process based on corn fiber. As corn fiber represents 8-9% of a corn kernel in dry weight, the country would start to generate more than 1 billion gallons of additional cellulosic ethanol every year.
What are you waiting for?
We work in an industry that often finds itself under public scrutiny. People point to technological barriers to full-scale, global commercialization; certain studies claim ethanol has a negative energy balance; and, others feel biofuels won’t happen fast enough to make a worthwhile impact in light of possible gasification, electrification and hydrogenization of the world’s car fleet.
Whether merited or not, these beliefs inhibit the growth of the corn ethanol industry. It’s therefore crucial that we make the most of the ground we’re given. Ethanol producers can start with the corn kernel.
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- Is corn fiber the next big opportunity for ethanol producers? - August 9, 2015