Glucose was first utilized due to the carbon catabolite
repression
(a common phenomenon observed in microorganism),
displaying sequential sugar ultilization when grown in the hydrolysate (Fig. 3a).
Xylose utilization was observed when glucose and arabinose were exhausted at 42 h
and cells cultured in 500 ml glass fermentor grew to the highest cell density (OD600) of 7.65.
The cells produced 14.26 g/L ABE solvents,
including 4.1 g/L acetone, 9.3 g/L butanol and 0.86 g/L ethanol.
The solvent productivity and yield reached 0.24 g/(L h) and 0.35 g/g.
The solvent concentration and yield was similar to batch fermentation using pure glucose as carbon source,
while the solvent productivity decrease 18%.
All supplied sugars were exhausted after 60 h fermentation,
suggesting that the hydrolysate with 41 g/L total sugars could be potential carbon resource for butanol fermentation.