Continuous simultaneous saccharification and fermentation of starch using Zymomonas mobilis.

A continuous process involving simultaneous saccharification and fermentation of liquefied starch has been developed using Zymomonas mobilis. Amyloglucosidase retention and cell recycle have been effected by using an Amicon hollow-fiber membrane system with a MW cutoff of 5000. Relatively high productivities of up to 60 g L(-1) h(-1) have been achieved at ethanol concentrations of 60-65 g/L. The system also offers the potential for reduced enzyme requirements for saccharification.