Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/11/2005
Publication Date: 8/1/2005
Citation: Nichols, N.N., Dien, B.S., Wu, Y., Cotta, M.A. 2005. Ethanol fermentation of starch from field peas. Cereal Chemistry. 82(5):554-558.
Interpretive Summary: Production of field peas is increasing in the U.S. The legume is grown as a short-season crop, or before or after another crop so that two crops can be harvested in one year. Although field pea protein has value as animal feed, the starch component of field peas is less valuable. Consequently, co-products that utilize the starch are needed. Ethanol production is a potential application because field peas have relatively high starch content, and in some cases, the crop is grown in the locality of ethanol plants. We have shown that field peas could be a feedstock for ethanol fermentation. Ground whole peas and an enriched starch fraction were fermented with good yields, using enzymes and procedures suitable for the corn-to-ethanol industry. This work provides the basis for making a value-added product from field peas.
Technical Abstract: Field peas (Pisum sativum) were evaluated as a potential feedstock for ethanol production. Ground peas were dry milled and separated into starch, protein, and fibrous fractions by air classification. Starch-enriched fractions prepared from whole peas and dehulled peas contained 73.7% wt and 77.8% wt starch, respectively, a nearly two-fold enrichment compared to whole peas. The fractions were liquefied and saccharified using industrial alpha-amylase and glucoamylase at recommended enzyme loadings. A final ethanol concentration of 11.0% (w/v) was obtained in 48-52 hr, with yields of 0.43-0.48 g ethanol/g glucose. Starch present in whole ground peas was also saccharified and fermented, with 97% of the starch fermented when an autoclaving step was included in the liquefaction stage.