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您的检索式：作者名="Nichole A.Bauer"
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| 1 | Saccharification versus simultaneous saccharification and fermentation of kraft pulp显示文摘Enzymes are a significant cost in cellulosic ethanol production,minimizing their use would be desirable as long as ethanol yields and productivities are not reduced.The aim was to evaluate the effects of enzyme dosage on conversion of cellulose to ethanol.Kraft pulp,an intermediate in paper production,was used to represent a fractionated cellulose feedstock.Trials were conducted in a 5 L BioFlow bioreactor(2-3 L working volume)with agitation rate varied(80-900 r/m)to provide acceptable mixing.Based on survey of the literature,an average dosage for cellulase(34 FPU/g glucan)andβ-glucosidase(135 CBU/g glucan)was calculated,and these were set as the 100%dosages.Dosages of 1%,7%,13%,33%,67%,100%,133%were tested,using Novozyme Celluclast 1.5 L(cellulase)and Novozyme 188(β-glucosidase)in a 4.8%(dry mass)kraft pulp slurry.Novozymes recommended dosages are at the low end of this spectrum,at 12 g/g glucan for Celluclast 1.5 L(35%dosage)and 1.2 g/g glucan for Novozyme 188(0.9%dosage).Saccharification trials(50oC)showed a typical dosage response,with the 133%dosage achieving the highest sugar concentration(~59 g/L glucose)and saccharification rate(2.45 g/L/h),with a specific rate of 2.2×10-4 g glucose/unit enzyme/h.However the 13%enzyme dosage resulted in the highest specific saccharification rate(2.9×10-4 g glucose/unit enzyme/h).Simultaneous saccharification and fermentation(SSF)trials(35oC)were conducted using Saccharomyces cerevisiae or Candida molischiana to compare enzyme dosages of 33%,67%,100%,and 133%.Ethanol titers and productivities were similar for trials with 67%or more of the literature average enzyme dosage,however were lower at the 33%enzyme dosage.Thus enzyme dosage can be substantially reduced from levels typically cited in the literature,but cannot be reduced to levels recommended by the manufacturer,without reduction in ethanol yield and productivity. | Nichole A.Bauer William R.Gibbons | 2012 | International Journal of Agricultural and Biological Engineering2012，5，1： | 0 |
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