DEVELOPMENT OF A LOW-COST, INDUSTRIALLY SUITABLE MEDIUM FOR THE PRODUCTION OF ACETIC-ACID FROM CLOSTRIDIUM-THERMOACETICUM

To develop a low-cost, industrially suitable medium for acetic acid pr oduction from Clostridium thermoaceticum, two waste by-products of cor n ethanol production were evaluated as replacements for the most expen sive ingredients in modified Ljungdahl's medium (MLM). Condensed corn solubles (CCS; 66.7 g/l dry matter) resulted in an acetate productivit y (0.33 g/h per litre) equivalent to that in MLM during fed-batch ferm entation. Yields in CCS medium were often above the theoretical maximu m owing to an unquantifiable substrate in the CCS. Although acetate co ncentrations in MLM were somewhat higher (35 g/l) than in CCS medium ( 32 g/l) it seems possible that further acclimation of the microbe coul d improve acetate production. CCS medium costs of $163/ton (1 U.S. ton = 907 kg) of calcium magnesium acetate (CMA) produced compare favoura bly with that of MLM ($6973/ton of CMA produced).