Production of ethanol by simultaneous saccharification and fermentation from Jerusalem artichoke flour

Based on the ability of Schizosaccharomyces pombe to ferment inulin-containing extracts into ethanol, the production of fuel ethanol by simultaneous saccharification and fermentation (SSF) using Jerusalem artichoke flour as raw material was presented. The effects of raw material treatment, Jerusalem artichoke flour concentration, initial pH value on the ethanol fermentation performances of Schizosaccharomyces pombe were investigated in a shaking flask, at the same time, the effects of the constant-pH fermentation and the uncontrolled-pH fermentation, aeration rate on the ethanol fermentation were also studied in a 5 L jar fermenter. Experimental results showed that the optimum initial pH value was 4.0, Jerusalem artichoke flour particle size was below 0.15 mm, high temperature treatment at 115℃ for 35 min was better than that at 121℃ for 20 min. According the optimum conditions for producing fuel ethanol, the maximum ethanol yield of 66.58 g/L, equivalent to 85.88% of the theoretical yield, was obtained for the slurry with a solid concentration of 200 g/L at 30℃ after 48 h of incubation in a shaking flask. The decrease of pH value of the broth had little effect on ethanol fermentation. The aerobic condition resulted in lower ethanol yield than strictly anaerobic condition and non-aeration condition. The ethanol concentration was a little difference between strictly anaerobic condition and non-aeration condition. Ethanol production by fed-batch fermentation was investigated and the maximum ethanol concentration of 94.81 g/L, equivalent to 81.54% of its theoretical value, was reached with final Jerusalem artichoke flour of 300 g/L in a 5 L jar fermenter. These results provide a scientific basis for fuel ethanol production from Jerusalem artichoke.