Rapid ethanol production from sucrose without by-product formation

Summary Non-sorbitol-producing Zymomonas mobilis ACM 3963 was developed from Z. mobilis UQM 2716. This strain was co-immobilised with invertase in alginate and incubated on sucrose-based media. This combination allowed theoretical yields of ethanol to be produced from 100 and 150 g/l sucrose, using both semi-defined media and sugar-cane syrup. No sorbitol or fructo-oligosaccharides were formed in either fermentation. Increased biomass concentrations immobilised in alginate reduced the batch fermentation times of 100 and 150 g/l sucrose by 50–70%, to 3 and 5 hours respectively. This strain also improved the efficiency of the fed-batch fermentation of sucrose.