A small amount of biobutanol
Fructose is more preferable for biobutanol production by C. acetobutylicum. In biobutanol Ginsenoside Rb1 using mixed sugars of glucose and fructose by C. acetobutylicum, the fructose utilization was significantly improved comparing to glucose under same conditions of oxidation–reduction potential .
It was found that when Clostridium thermoaceticum was grown in a mixture of glucose and fructose, the utilization of glucose does not start until the fructose is almost completely depleted . The study concluded that fructose inhibited the fermentation of glucose due to the competition between glucose and fructose as substrates for the enzyme involved in active transport of the sugars into the cell, or a repression by fructose of the synthesis of an enzyme needed for glucose utilization .
The first reaction in fructose catabolism is the formation of fructose 1-phosphate by phosphoenolpyruvate (PEP):fructose phosphotransferase while the first catabolism of glucose is the formation of glucose 6-phosphate via phosphoenolpyruvate (PEP):glucose phosphotransferase then to fructose 6-phosphate by glucose-6-phosphate isomerase .