Microalgae have great potential for providing sustainable animal feeds. They contain all the desirable macro- and micro ingredients animal nutrition requires and the oil they contain can be used as a biofuel. A bright future lies ahead. A parallel with the development of the bio-ethanol industry with its co-product DDGS can be drawn, however, with a clear-cut difference: governmental financial support is far less or even absent.
By Dick Ziggers
When browsing the web on information about the use of algae in animal feeds one almost becomes euphoric about the great versatility of this family of water plants and the great benefits it has for animal performance. Just some statements I came across in poultry:
“Increases egg laying period from 14 months to 24 months”, “Decreases mortality rates from 10% to less than 2%” and “Significantly better taste” (of what?). In cattle there is talk of “Increases quantity of milk and healthier and better tasting milk”, “Increases ‘good’ butter fat percentage (?)” and a most remarkable one: “Prevents and reduces incidence of encephalopathy or Mad Cow Disease”. Indeed a miracle crop, one would think. Despite these (too) broad statements algae as a feed stock still has a great potential.Algae can be cultivated in human-made ponds on otherwise unusable desert land, requiring only sunlight and seawater to grow. In an optimal situation it’s about 30 times more productive than soy, but requires only 1% as much fresh water. It also has a much higher protein content. “If we could use this biomass to replace soybeans, then we could have a lot of soybeans left for human consumption,” explained Xingen Lei, a Cornell professor who’s been testing algae as an animal feed supplement.Lei’s research is funded by a $5.5 million government grant to investigate algae’s role in solutions to alarming food and energy crises. Since the early eighties, for almost two decades the US government funded research into algae’s potential as a biofuel. It stopped the program in 1996 after concluding that algal biofuels could not be cost-competitive with fossil fuels. Current oil prices however have renewed attention from investors as a potential fuel source.
“Current animal feed directly competes against human food sources and, thus, is unsustainable,” Lei said. “We must develop alternatives to soybean and corn for animal feeds.” Algae produces 50 times more oil per hectare than corn, with a much smaller carbon footprint; uses nutrients more efficiently than land plants, with no runoff; and places no demand on high-quality agricultural land or freshwater supplies.
There are an estimated 1 billion swine worldwide. The average pig consumes about 300 kg of feed by the time it goes to market, Lei said, so replacing just 10% of that feed with algae would save a massive 30 million tonnes.Lei’s preliminary research found that dried defatted algae derived from biofuel production can replace up to one-third of soybean meal in diets for pigs and chickens. It is an attractive source because it is high in protein: 20-70%, compared with about 10% in corn and 40% in soy. Lei and his researchers are now working to determine which algae are best, and the proper ratios of algae, soybean and corn. They are also discerning whether there are risks or additional health benefits for humans in resultant products, such as meat and eggs.
Samples are shipped to Lei’s lab from Hawaii, where algae is being cultivated on a few acres near the Kailua Kona Airport as part of a $15 million pilot project by Cellana and a multi-university consortium led by Cornell professors Chuck Greene, professor of earth and atmospheric sciences, and Jeff Tester, professor of chemical and biomolecular engineering.
Ramping it up to commercial scale will require thousands of acres and hundreds of millions of dollars, said Greene.
Which is where Lei can help. Turning a biofuel by-product into a value-added product could be the key to commercial viability and may spawn other new industries. The global animal feed market is expected to exceed 1.5 billion tonnes per year by 2020, 15% of which is protein, Lei said.
Lei’s algae are a dried version of their single-cell species. Their simple structure means it is easier to break down, without the complex cellulose that presents challenges to the production of plant-based biofuels like corn-derivedethanol. It also has a high lipid, or oil, content - around 30%, compared with 4% in corn - and its own inherent stress response can be harnessed to help in oil production. When starved of nutrients, the algae undergoes physiological changes causing it to exude oil - a process being studied by Beth Ahner, professor of biological and environmental engineering, and Ruth Richardson, associate professor of civil and environmental engineering.
With further innovations, the process could actually remove substantial amounts of carbon dioxide from the atmosphere, Greene said, and its use in the production of jet fuel could help the US military meet its goal of switching to a 50/50 blend of fossil and biofuels by 2020. Greene said that even with today’s high fossil fuel costs, algal biofuels will likely become cost competitive with fossil fuels only when valuable co-products are simultaneously exploited and commercialised.So, it is similar to the early stages of bioethanol production from corn, where the remaining distillers grains were almost considered a waste product, but when subsidies were lessened they became a valuable material that added to the profitable exploitation of the ethanol plant. Converting the algae biomass, that is left behind after extracting the oil, to commercially viable feed increases the overall value of algae as a resource. This makes algae’s animal feed application so significant and gives algal biofuel a value-added component that makes it much more attractive to investors. Another benefit of the algae biomass is that when extracting the oil for fuel the protein content in the remaining product increases, making it potentially more ideal as a feed source. “Most calculations do not factor in the animal feed application,” Lei said. “If you put that in, the equation would shift significantly. It’s mutually beneficial.”But funding still presents a huge barrier; moving pilot projects to a commercial scale would require hundreds of millions of dollars. If governmental subsidies would shift from bioethanol and biodiesel projects to algae projects these would definitely have a better chance.
All About Feed Vol 20 issue 6