A bioreactor system with a total working volume of 4. 8 L, composed of four airlift suspended-bed bioreactors, one of which was designated for seed cultivation and the others in series for ethanol fermentation, was established and continuously operated for 40 days. A self-flocculating fusant from Saccharomyces cerevisiae and Schizosaccharomyces pombe (SPSC01) was used and ethanol and yeast were co-produced from corn dry milling, two-stage enzymatic hydrolysis (raw material residues were separated after saccharification). The results showed that average levels of 98 g · L-1 for ethanol, 4 g · L-1 forresidual reduced sugar and 6-9 g · L-1 for residual total sugar were achieved when the medium containing total sugar of 220 g · L-1 was fed at a dilution rate of 0. 05 h-1. Pure yeast, equivalent to 5% (mass) of ethanol and containing protein as high as 48. 6% (mass), was co-produced. Ethanol production is expected to be more economically competitive as this high quality yeast potentially can be further processed as value-added by-products.
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