Ethanol production by a mixed culture of flocculent strains of Zymomonas mobilis and Saccharomyces sp

Pure and mixed cultures of Zymomonas mobilis and Saccharomyces sp. were tested for the production of ethanol using sucrose as the carbon source. Both strains, isolated from spontaneously fermenting sugar-cane juice, are flocculent and alcohol-tolerant. The best results were obtained using a mixed culture, with a yield of 0.5 g ethanol/g sugar consumed and a volumetric productivity of 1.5 g ethanol 1-1 h-1. No levan was produced even if a sucrose-based medium was used.