Novel Technologies for Enhanced Production of Ethanol: Impact of High Productivity on Process Economics

摘要

In these studies Saccharomyces cerevisiae NRRL Y-566 was used to produce ethanol from a concentrated glucose (250-300 gL -1 ) solution. When fermentation media were supplemented with CaCO 3 and CaCl 2 , ethanol concentrations, yield, and productivities were improved significantly. In control batch fermentation, the culture was able to produce 20.87 gL -1 ethanol with a productivity of 0.25 gL -1 h -1 when using 100 gL -1 sugar solution in feed. When supplemented with a solution of 0.40 gL -1 CaCl 2 , ethanol concentration, yield, and productivity were improved to 90.0 gL -1 , 0.48, and 1.25 gL -1 h -1 (500% increase), respectively. The effect of CaCO 3 supplementation was not as pronounced as that of CaCl 2 . Using these parameters, the process economics for production of ethanol was performed and it was projected that supplementation with 0.40 gL -1 CaCl 2 would result in the production of ethanol for $0.91 kg -1 . It was also projected that improving productivity to 37.5 gL -1 h -1 using cell recycle and supplementation with CaCl 2 would result in the production of ethanol for $0.70 kg -1 employing S. cerevisiae NRRL Y-566. Using Z. mobilis in membrane cell recycle reactors and application of CaCl 2 can result in achieving high productivities (500-600 gL -1 h -1 ) and reduction in ethanol production price to $0.59 kg -1 .