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 Lenconostoc 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 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.