Written by Jonathan Eisenthal
With a few small changes to improve the nutritional profile of distillers grains, also known as DDGS, research scientists at the University of Minnesota hope to deliver a triple win.
A mid-protein, high-phosphorus animal feed, distillers grains are an ethanol co-product made from corn after fermentation. The enriched distillers grain these researchers hope to produce would deliver more nutrition, offer another co-product to increase profits for ethanol makers, and deliver an environmental benefit by reducing the phosphorous load in hog and poultry manure.
Leading the team is Bo Hu, a professor in the Department of Bioproducts and Biosystems Engineering at the U of M. According to Hu, today’s DDGS are short of certain amino acids. To compensate, livestock farmers either increase the volume of DDGS, which wastes value, or they add synthetic amino acids to balance out the feed ration, which is an added cost.
“We hope to increase the nutrition and lower the cost of DDGS, and add a value-added product that the ethanol plant can make money on,” Hu says.
Hu’s team is working on genetically re-engineering Saccharomyces (also known as brewer’s yeast) to accumulate more amino acids during corn-ethanol fermentation. Early trials show the amino acid Lysine can be doubled in volume in each yeast cell, bringing the nutritional profile of DDGS closer to that of soybean meal.
Meanwhile, chemical engineer Aravindan Rajendran is focused on the secondary fermentation process, where microorganisms grown in the ethanol co-products would then be mixed with DDGS to produce a better animal feed with higher protein.
The final piece of the investigation is to try to lower the phosphorous level in the DDGS.
Graduate student Cristiano Rodrigues Reis is working on a technology for extracting the phosphorous without affecting the other high-value nutrients present in the distillers grains. Phytate is the major form of organic phosphorous in corn, and is not digestible for single stomach animals like hogs and poultry. Not only does phytate pass through the animal to the manure, but it also has anti-nutritional properties.
However if phytate can be removed without reducing the nutritional value of the distillers grains, it can be marketed as a high-value industrial compound, according to Hu. Currently imported from China and Japan, phytate is a common ingredient in face cream and even as a human food ingredient.
According to Paul Meints, director of research for Minnesota Corn Growers Association, this distillers grain research is one of many exciting projects receiving funding through Minnesota’s corn organizations.
“We are excited about the diversity of research projects we have been able to fund,” says Meints. “We are looking at many different aspects of how to add value to our farmers’ corn through the use of the checkoff dollars. From improving DDGS, all the way down to green chemistry and sustainable polymers, these investments cover the gamut of what we do and how we do it with corn. The entire focus of our expanded uses team is developing more corn-based products for the marketplace.”