A team at the National Institute for Agro-Environmental Sciences in Japan has developed an efficient production of both ethanol biofuel and animal feed from one crop. Using rice, the predominate grass and starch crop in Japan, the work can be done on a farm without the need for an off-site processor.

The research has been published in the open access journal Biotechnology for Biofuels where it discusses the practical potential of an alternative to fossil fuels that does not compete with food resources.

First-generation’ biofuels include ethanol produced from food sources such as corn and sugarcane. While recognized as a renewable energy source that improves fuel security, their production has caused controversy over competing land-use for food and increased grain prices. The fermentation of non-food sources such as straw and wood, known as ‘second generation’ biofuels, has been promoted as a promising alternative, but also has its limitations.

First author Mitsuo Horita explained, “Generally, the bottlenecks in second generation biofuel production include the need for large facilities, bulky material transport and complicated treatment processes, all of which are costly and consume a great deal of energy.

“What we’ve now demonstrated is a complete and scaled-up system which shows its potential in a practical on-farm situation. Instead of a complicated process requiring special facilities, our system simply builds upon traditional processes already used by farmers for producing silage for animal feed. It results in a high yield of ethanol while producing good quality feed, with zero waste,” he said.

The process, known as ‘solid-state fermentation’, involves packing harvested whole rice plants with yeast and enzymes into a round bale wrapped in an impermeable film. During incubation, sugars and starch in the rice plant are converted by yeast to ethanol, which accumulates and is then drained and distilled for fuel, leaving a bale of high quality animal feed in the form of silage.

In the tests, the process yielded up to 12.4 kg of pure ethanol per bale, after six months of incubation – ten times more ethanol than would result from natural silage production. A steady amount of ethanol also continuously drained out in the effluent from the bale during the test, resulted in an additional 1.7 kg of ethanol that could be easily collected without extraction.

The remaining bale material was found to be comparable to normal silage for animal feed, containing a similar amount of lactic acid and sugars, and high crude protein content – an essential dietary component for cattle.

Although the system requires a relatively long time for fermentation, no energy needs to be supplied into the system. The use of a vacuum distiller allowed the extraction of a total of 86% of the ethanol that accumulated in the bale. The ethanol also contained no insoluble particles, and could therefore be easily dehydrated and concentrated for use as automotive fuel.

The research shows the potential for complementary food and biofuel production, circumventing issues related to land-use competition. The system could be deployed at a local level by individual farmers, providing sustainable biofuel production, and could be particularly beneficial to farmers in the developing world.

The authors note that further studies into improving the ethanol yield and recovery ratio, and an environmental assessment of the system’s complete life cycle, should also be carried out before the system is widely established in rural areas.

Its actually better news than a first impression. A quick look through the study shows that the bale of whole fresh rice weighed 244 kilograms (538 pounds, a quite small bale by U.S. practices.) or just 125 kilograms (275 pounds) dry weight. That’s 14.1 kilograms (31 pounds) of ethanol, pulling 11% of the dry weight to fuel.

This is sure to seize the attention of America’s corn farmers. An American sized bale of corn silage, if it responded the same as rice, might make over 100 pounds of ethanol or more than 15 gallons perhaps something like 225 gallons per acre that at today’s price is worth $315.00.

These researchers have made a great start, there is a long way to go. But for consumers the idea of pulling out the fuel and still having the food value still there is very attractive.


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