THE PRODUCTION OF 2,3-BUTANEDIOL BY FERMENTATION OF HIGH TEST MOLASSES

Klebsiella oxytoca fermented 199 g.l-1 high test or invert molasses using batch fermentation with substrate shift to produce 95.2-98.6 g 2,3-butanediol.l-1 and 2,4-4.3 g acetoin.l-1 with a diol yield of 96-100% of the theoretical value and a diol productivity of 1.0-1.1 g.l-1.h-1. Fermentation was performed numerous times with molasses in repeated batch culture with cell recovery. Such repeated batch fermentation, in addition to a high product yield, also showed a very high product concentration. For example, 118 g 2,3-butanediol.l-1 and 2.3 g acetoin.l-1 were produced from 280 g.l-1 of high test molasses. The diol productivity in this fermentation amounted to 2.4 g.l-1.h-1 and can undoubtedly be further increased by increasing the cell concentration. Because the Klebsiella cultures ferment 2,3-butanediol at an extremely high rate once the sugar has been consumed, the culture was inhibited completely by the addition of 15 g ethanol.l-1 and switching off aeration.