Succinic acid production with reduced by-product formation in the fermentation of Anaerobiospirillum succiniciproducens using glycerol as a carbon source

Succinic acid was produced by fermentation of Anaerobiospirillum succinicip roducens using glycerol as a carbon source. When cells were anaerobically c ultured in a medium containing 6.5 g/L glycerol, a high succinic acid yield (133%) was obtained while avoiding the formation of by-product acetic acid . The gram ratio of succinic acid to acetic acid was 25.8:1, which is 6.5 t imes higher than that obtained using glucose (ca. 4:1) as a carbon source. Therefore, succinic acid can be produced with much less by-product: formati on by using glycerol as a carbon source, which will facilitate its purifica tion. When glucose and glycerol were cofermented with the increasing ratio of glucose to glycerol, the gram ratio of succinic acid to acetic acid and succinic acid yield decreased, suggesting that glucose enhanced acetic acid formation irrespective of the presence of glycerol. Glycerol consumption b y A. succiniciproducens required unidentified nutritional components presen t in yeast extract. By intermittently feeding yeast extract along with glyc erol, a high succinic acid yield (160%) could be obtained while still avoid ing acetic acid formation. This resulted in the highest ratio of succinic a cid to acetic acid (31.7:1). (C) 2001 John Wiley & Sons, Inc.