Fishing For Profit

Distillers grains and other new coproducts of ethanol production show potential in replacing fishmeal, the holy grail ingredient in aquaculture feed rations.
By Holly Jessen | June 11, 2014

Ethanol producers looking for the next big market for distillers grains may want to seriously consider aquaculture feed. “For a variety of reasons, we’re just at beginning phases of seeing the potential for a significant amount of DDGS use in fish diets around the world,” says distillers grains expert Jerry Shurson, a professor at the University of Minnesota. 

Fishmeal, part of the aquaculture ration, is expensive and growing more so all the time. There are also questions about the long-term sustainability of harvesting wild-caught marine fish from the ocean. “It has put a lot of pressure on the aquaculture industry, globally, to look for alternative protein sources to replace some, if not all the fishmeal,” he says.

That, plus rapid growth in the farmed-fish industry, has opened up a huge potential for plant-based protein substitutes, including distillers grains. Testing has shown that ethanol coproducts contain very attractive nutritional components for fish. “It’s one of the little-known stories about future markets that really have not been developed to its fullest extent,” Shurson says, adding that he expects to see more as ethanol plants evolve into true biorefineries. In fact, Badger State Ethanol LLC is currently using Fluid Quip Inc. technology to break into this and other markets. “They are producing a very high-quality, high-protein, high-amino acid coproduct, which has features that are very, very attractive for aquaculture feed, as well as for pig diets and poultry,” he says.

In Belgium, BioWanze SA, a 300,000 cubic meter (80 MMgy) wheat-to-ethanol plant produces 55,000 metric tons a year of gluten. Besides going into the pet food and baked goods market, the company’s pelletized gluten is a popular replacement for imported fishmeal or high protein soy concentrate, says André Tonneaux, director of BioWanze SA.

These two ethanol producers aren’t the only ones with their eye on the fish food prize. In South Dakota, Prairie AquaTech is perfecting a microbial process to convert soybean meal or distillers grains into a high-protein, low-fiber aquaculture feed. It involves inoculating the plant-based feed ingredient with a microbe that consumes carbohydrates in a process similar to fermentation, says Jason Bootsma, the company’s chief technology officer.

Although the company has been working with soybean meal longer, researchers have already discovered that distillers grains has a few advantages. Besides a lower price, distillers grains has fewer anti-nutritional properties than soy, he says. On the other hand, soy starts out with a higher protein level than distillers grains, a key factor in identifying an ideal fishmeal replacement. Fishmeal, which runs about $2,000 a ton, is 65 percent protein. Prairie AquaTech has successfully used its process to produce a soybean meal feed that can replace 100 percent of fishmeal in aquaculture ration. “We haven’t quite got to that level yet with distillers grains,” he says. “We’re still working on that.”

Investigating The Possibilities
Shurson was part of a study of distillers grains used in aquaculture diet that was conducted in Norway, which compared the effects of including distillers grains without distillers corn oil separation and reduced-oil distillers grains. Although it was assumed low-oil distillers grains would be better for aquaculture feed due to a higher protein content, that didn’t turn out to be correct, he says. Both types of distillers grains worked well in aquaculture diets and show potential but reduced-oil distillers grains was slightly less attractive.

In this study, rainbow trout were fed a diet in which distillers grains were used as a partial replacement for other plant based proteins, such as canola meal, sunflower meal and field peas. The fish that were fed high-oil distillers grains had better feed conversion, weight gain and other benefits. Those that got low-oil but higher protein distillers grains actually experienced lower protein digestibility but better phosphorus retention and digestibility.

Peter Williams, the biofuels business development manager for Associated British Agriculture, spoke last year at the International Fuel Ethanol Workshop & Expo about a potential new ethanol coproduct he calls yeast protein concentrate (YPC,) which is a good replacement for fishmeal in aquaculture diets. In fish feeding trials YPC was used at up to a 15 percent inclusion rate with good results. “Not only was it able to replace the fish meal, but we got some very important increase in growth when we put this product in,” he says, adding that yeast is a known immune stimulant that contains valuable components such as nucleotides.

William’s work in this area got started when he wondered how much yeast went through the ethanol production process. No one could answer that question. “We found it’s a lot more than was first realized,” he says, adding that the amount of yeast increases during fermentation. Associated British Agriculture is in the process of patenting the technology to recover yeast and working to license it with ethanol producers in the U.S. and overseas.

Dennis Evers, chief technology officer for Meridian Biotech, will speak on this topic at this year’s FEW. The company has developed a process to grow bacterial biomass on waste products, such as ethanol stillage. The biomass, a single-cell protein, doubles in volume rapidly and can generate about 10 tons a day. An ethanol plant could potentially go from a 12-cent per gallon profit on the ethanol it produces to a 28-cent per gallon profit, just by adding production of this new coproduct, he says. Another benefit is that the methane generated during the process can be captured to supply all the facilities energy needs.

Testing conducted in Australia on prawns revealed phenomenal results, including a faster growth rate. “They liked it so much they were virtually jumping out of the water,” he says. “They just loved the stuff.” 

Meridian Biotech is currently working on joint ventures with U.S. ethanol producers, including companies that own multiple ethanol plants.  Evers has had 40 years to work the teething problems out of the process, he says, which is ultimately very simple. “This is what people can’t understand. It has so many benefits, yet it is so simple. In fact, it’s too bloody simple, actually,” he says with a laugh. “I should make it look a bit more complicated.”

Big Potential
Adel Yusupov, regional director for Southeast Asia for the U.S. Grains Council says worldwide aquaculture feed production is estimated at 70 million metric tons yearly. Seventy percent of that is produced in China, 18 percent in Southeast Asia and 6 percent in India. “Globally, wild catch has been trending down, while aquafarming is on uptrend,” he says. “It is not a matter of if, but when, that the aquaculture industry will have to move feeding from fish-based (fishmeal, trash fish) toward plant-based protein feed ingredients such as soybean meal, distillers grains and corn gluten meal.”

USGC has done some feeding trial work, promoting distillers grains and corn gluten meal in aquaculture diets. There is a potential market for U.S. ethanol producers in the Asian aquaculture market, he says. “It is still small-niche usage area, compared to bigger poultry and swine markets, but offers strong growth potential,” he says.

Michael Franko, technical projects manager for Fluid Quip, confirms it’s a market with huge opportunity. “Everybody wants to be in aqua,” he says. Besides the technology in operation at Badger State since 2009, Fluid Quip is working with two international plant projects, currently in the detailed engineering phase, which aim to produce the same high-protein coproduct. In addition, in early May, the company was issued a notice of allowance for its patent application.

Producing a new ethanol coproduct like the ones described by Evers, Franko and Williams does change the composition of the distillers grains produced. Specifically, the Fluid Quip process results in about 3 to 4 fewer pounds per bushel of distillers grains, on a dry basis, Franko says. However, besides a second, high-value coproduct, the process can also result in more distillers corn oil. And, it’s tunable, with the ethanol producer having the ability to adjust the concentration percentages of the yeast, gluten or protein, which can go to concentrations as high as 55 percent.

Author: Holly Jessen
Managing Editor, Ethanol Producer Magazine