Extraction and purification of lactic acid from silages

Various silages with different contents of organic acids were used to evalu ate the possibilities of recovery of lactic acid from grass silages. Press extraction yields of lactic acid from silage preparations ranged from 31 to 96 g lactate per kg silage dry matter (g LA/kg DM). The crude liquid press extract was pre-treated with ultrafiltration membranes followed by purific ation with mono-polar electrodialysis (ED). Low current densities, high ene rgy consumption at 1.47-1.76 kWh/kg lactate and the high levels of organics and minerals (8 g/l) limit the possible applications of the resulting prod uct to low-grade applications such as animal feed additive or road-de-icers . (C) 2000 Elsevier Science Ltd. All rights reserved.