Bioresource Technology, Vol.274, 343-352, 2019
Improvement on bioprocess economics for 2,3-butanediol production from very high polarity cane sugar via optimisation of bioreactor operation
This study focuses on the optimisation of 2,3-butanediol (BDO) production in fed-batch cultures carried out with the bacterial strain Enterobacter ludwigii using very high polarity (VHP) sugar from sugarcane mills. Various k(L)a values were evaluated using either complex or synthetic fermentation media demonstrating that the latter enhance BDO production efficiency with low by-product formation. The pH (6.3) and temperature (33.9 degrees C) employed in fed-batch bioreactor cultures has been optimised via experimental design. Fed-batch cultures carried out at the optimum temperature and pH and varying k(L)a values resulted in BDO concentration, yield and productivity of 86.8 g/L, 0.37 g/g and 3.95 g L-1 h(-1). Using this fermentation efficiency, the minimum selling price of BDO for annual production capacities of 10,000 t and 50,000 t was estimated at $3.12/kg and $2.67/kg, respectively, for a VHP cane sugar market price of $0.4/kg.
Keywords:2,3-butanediol;Enterobacter ludwigii;Fermentation optimisation;Volumetric oxygen transfer coefficient (k(L)a);Techno-economic evaluation