- Soybean Hulls
SBH Biofuel Systems Inc. has filed patents in the U.S., Brazil, and Argentina, and is seeking a commercial partner for this technology.
Soybean hulls haven’t been widely considered for ethanol production because of their existing market as livestock feed. With this enzyme-based ethanol production process, the soybean hulls can produce ethanol, feed livestock, and act as a food additive suitable for human consumption. Experiments showed that a ton of soybean hulls can produce up to eighty five gallons of ethanol. With the approximately five million tons of soybean hulls produced annually in the U.S., this method could produce 450 million gallons of ethanol and 450,000 tons of high-protein food additives per year. Brazil and Argentina have soybean crops on par with the United States, as well as ethanol production facilities and the infrastructure necessary to use ethanol as a fuel.
- Excellent Feed Source
Excellent feed source for single-stomached or ruminant animals.
This process for generating ethanol fuel from soybean hulls leaves the soy protein intact so that the hulls remain viable for use as a food additive and feed for livestock and animals. Because of their unique mix of carbohydrates, soybean hulls are capable of producing three to four times more ethanol fuel than corn or wheat crop residues or the dedicated biomass source switchgrass. The hulls contain between 9 and 14 percent protein, which they retain through the fermentation process, making them an excellent feed source for single-stomached or ruminant animals.
- Fewer Costs and Reduced Time
Using only low levels of the enzymes, engineers were able to signiﬁcantly de-polymerize the complex carbohydrates in soybean hulls in order to permit the yeast to ferment ethanol. Soybean hulls proved far more susceptible to these enzymes than corn stover, wheat straw, and switchgrass. Two genetically engineered bacteria also proved effective in fermenting soybean hulls to ethanol. Ethanol conversion from other crop residue and biomass materials requires expensive thermo-chemical pretreatment that accounts for an estimated 18 percent of ethanol production costs, or 50 cents of a $2.50 gallon of ethanol. Soybean hulls need only enzymes to start the simultaneous saccharification and fermentation process that creates ethanol. Tests of biomass loadings from five to 20 percent concentration demonstrated that the saccharification and fermentation process could produce essentially proportional ethanol concentrations over the whole range of feedstock levels, permitting signiﬁcant ﬂexibility in fermentation.
- In The News
Fermentation of Soybean Hulls to Ethanol While Preserving Protein Value
- History of Technology
This cutting edge soybean ethanol technology was developed at Dartmouth University by Dr. Jonathan Mielenz in 2009. Dr. Mielenz is the group leader for the Bioconversion Science and Technology Division at the Oak Ridge National Laboratory. Mr. Mielenz is also co-chair of the long-running Symposium on Biotechnology for Fuels and Chemicals.