ARS | Publication request: UTILIZATION OF FUEL ETHANOL RESIDUES IN PRODUCTION OF THE BIOPOLYMER ALTERNAN

Submitted to: Process Biochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 27, 1997
Publication Date: N/A

Interpretive Summary: The fuel ethanol industry has become an important partner to American agriculture, but ethanol still has difficulty competing economically with imported petroleum. In order to offset the relatively high cost of ethanol production, we sought to identify new value-added coproducts that could be made from fuel ethanol residues. Corn condensed distiller's solubles (CCDS) is an abundant byproduct of fuel ethanol production from wet-milled corn, currently used as a component of low- value animal feeds. Alternan is a unique biopolymer with potential commercial applications in foods, cosmetics, etc. Microorganisms that produce alternan require expensive nutritional supplements such as liver extract or beef extract. In commercial production, such nutrients would likely be limiting due to price and availability. We found that CCDS could serve as an inexpensive replacement for these costly ingredients. This finding could reduce the cost of alternan production and provide a new value-added use for CCDS. Results should be of value to fuel ethanol producers, who are looking for new co-product markets to enhance the economic competitiveness of their industry. Enhanced production of ethanol should in turn benefit farmers by providing expanded markets for corn products.

Technical Abstract: Corn condensed distiller's solubles (CCDS), an abundant byproduct of fuel ethanol production from wet-milled corn, was utilized as a fermentation medium component in the production of alternan by Leuconostoc mesenteroides. Complex components of a conventional alternan production medium were completely replaced with CCDS at 1.5% w/v. L. Mesenteroides strains NRRL B-1355 and NRRL B-21138 grew to higher cell densities in CCDS medium than in conventional medium, and produced biopolymer more rapidly. However, stationary-phase cultures of strain NRRL B-21138 lost viability in CCDS medium, suggesting that CCDS might be most suitable for batch production of alternan.