Bioconversion of biodiesel-derived glycerol into 2,3-butanediol has received recently much attention due to its increasing surplus and its multiple uses in industry as bulk chemical. The influence of initial glycerol concentration on 2,3-butanediol production in batch runs has been studied. A concentration higher than 140 g/L produces an inhibitory effect on the final 2,3-butanediol concentration and its production rate. In batch mode, the highest yield respect to the theoretical maximum yield (71%) was reached employing 140 g/L as initial concentration 140 g/L. Based on these results, a high 2,3-butanediol production has been achieved through a fed-batch strategy. The reached 2,3-butanediol concentration was 90.5 g/L from pure glycerol and 80.5 g/L from raw glycerol. The 2,3-butanediol yield respect to the theoretical maximum yield was also improved through the fed-batch operation (90%). To date, this concentration is the highest produced amount employing as biocatalyst a non-pathogenic bacterium (level 1).
Keywords: 2,3-Butanediol; Biorefinery; Raoultella terrigena; Raw glycerol.