Study Of ABE Production From Fresh Potato

A comparative study of Clostridium acetobutylicum B-5 and C.acetobutylicum H which were preserved in our laboratory was carried out.The liquefaction conditions of ABE fermentation from cassava were studied.The dosage of a-amylase for these two strains were 3.5 U/g and 1.5 U/g,respectively,and the liquefaction time of both strains were 15min.The amylase activity and fermentation ability of C.acetobutylicum H were higher than those of the C.acetobutylicum B-5.Both of the two strains can assimilate a wide range of carbon source.The butanol tolerance of H was higher than that of B-5.ABE fermentation by C.acetobutylicum H with fresh potato as fermentation substrate was studied.By single factors experiment and response surface analysis optimization,the optimum medium component of fermentation were:the initial concentration of sugar was 95 g/L,the soybean meal is 4.2 g/L,and the FeSO4.7H2O is 0.07 g/L.Single factors experiment was carried out to determine the best cultivation conditions and the results were:the cultivate time for inoculum was 20 h,inoculum size was 10%,fermentation temperature is 37?,liquid medium volume was 150mL in 250mL-flask,initial pH was 6.5.The yield of butanol and total solvent under the optimum condition were 17.24 g/L and 30.80 g/L,respectively,which was 14.7%and 20.1%higher than those on original condition.The kinetic parameters including pH,acid production,solvent production,the residual total sugar and residual reducing sugar during the process of ABE fermentation by C.acetobutylicum H using fresh potato in a 10 L fermenter were investigated.There were three stages during the process of fermentation including the acid accumulation period(0?12 h),the main fermentation period(12 h?30 h)and the after fermentation period(30h?60 h),respectively.The production rate of butanol,acetone and ethanol were 0.383 g/L-h,0.215 g/L-h and 0.073 g/L-h,respectively,the starch consumption rates was 2.17 g/L-h.At the end of fermentation,the yield of butanol,acetone and ethanol were 17.67 g/L,10.73 g/L and 3.07 g/L,respectively.The residual total sugar was 15 g/L;the residual reducing sugar was 8 g/L.