"Green juice", obtained by squeezing fresh alfalfa leaves inoculated with lactic acid bacteria, was fermented at room temperature for 7-21 d to obtain 12-47 g lactic acid L-1. Inoculation of green juice with Streptococcus bovis and incubation at 39 degrees C reduced fermentation time to 8-12 h. The resulting "brown juice" from either fermentation had a pH of similar to 4.5 and a protein precipitate. Upon adjustment to pH 5.2-6.8 and inoculation with Megasphaera elsdenii, brown juice was fermented within 48 h to up to 18 g of mixed volatile fatty acids (VFA) L-1. Single-stage fermentation of green juice by both species in coculture typically resulted in overgrowth of S. bovis and acid inhibition of M. elsdenii, inhibiting VFA production. Because the juice fermentations are conducted without sterilization or supplemental nutrients, they can potentially contribute to an integrated process featuring protein recovery and fermentation of fractionated solids to VFA and other products. Published by Elsevier Ltd.