The aim of this work is to evaluate the efficiency of ethanol production by fermentation of a hydrolysate obtained by the enzymatic hydrolysis of purple elephant grass （Pennisetum purpureum Schum.） using a blend of ...The aim of this work is to evaluate the efficiency of ethanol production by fermentation of a hydrolysate obtained by the enzymatic hydrolysis of purple elephant grass （Pennisetum purpureum Schum.） using a blend of cellulases. Three hundred grams of 20-mesh granulated purple elephant grass was subjected to hot water pretreatment at 100 ℃ for a period of 25 min in a batch autoclave reactor. The pulp obtained from the pretreatment process was washed with water at 60 ℃ and submitted to enzymatic hydrolysis using a combination of exoglucanases, endoglucanases and beta-glucosidases or β-glucosidases from Novozymes. The pH of the system was kept constant at 4.8 by adjusting the levels of acetic acid or sodium acetate in the buffer solution. Enzymatic hydrolysis occurred at 50 ℃ upon agitation at 200 rpm on a shaker for 72 hours. The hydrolysate obtained after agitation was fermented using dried Saccharomyces cerevisiae yeast （manufactured by Dr. Oetker） at 30 ℃ for 10 hours. The liquids obtained after fermentation were analysed using HPLC to determine the quantity of ethanol produced. After 4 hours of fermentation, the maximum quantity of ethanol was 1.8 g/L. The stoichiometric yield of ethanol was approximately 95%. However, the step ofpretreatment was deemed unsatisfactory due to the loss of glucose during the pretreatment process.展开更多
文摘The aim of this work is to evaluate the efficiency of ethanol production by fermentation of a hydrolysate obtained by the enzymatic hydrolysis of purple elephant grass （Pennisetum purpureum Schum.） using a blend of cellulases. Three hundred grams of 20-mesh granulated purple elephant grass was subjected to hot water pretreatment at 100 ℃ for a period of 25 min in a batch autoclave reactor. The pulp obtained from the pretreatment process was washed with water at 60 ℃ and submitted to enzymatic hydrolysis using a combination of exoglucanases, endoglucanases and beta-glucosidases or β-glucosidases from Novozymes. The pH of the system was kept constant at 4.8 by adjusting the levels of acetic acid or sodium acetate in the buffer solution. Enzymatic hydrolysis occurred at 50 ℃ upon agitation at 200 rpm on a shaker for 72 hours. The hydrolysate obtained after agitation was fermented using dried Saccharomyces cerevisiae yeast （manufactured by Dr. Oetker） at 30 ℃ for 10 hours. The liquids obtained after fermentation were analysed using HPLC to determine the quantity of ethanol produced. After 4 hours of fermentation, the maximum quantity of ethanol was 1.8 g/L. The stoichiometric yield of ethanol was approximately 95%. However, the step ofpretreatment was deemed unsatisfactory due to the loss of glucose during the pretreatment process.
