원문정보
초록
영어
Kluyveromyces marxianus 17555-DF-33 was engineered by integration of KmXYL1 and KmXYL2 genes into K. marxianus 17555ΔURA3 by random integration method. After random integration of KmXYL1 and KmXYL2 genes, K. marxianus 17555-DF-33-14 strain was isolated for efficient ethanol production from xylose, through a directed evolutionary approach. In order to optimize fermentation conditions, agitation and medium pH conditions were varied using bioreactor. Xylose consumption rate, xylitol production rate and ethanol production rate were 1.50 g/L∙h, 0.73 g/L∙h and 0.02 g/L∙h, respectively at 600 rpm. However, ethanol production rate was 6 fold higher at 500 rpm (0.12 g/L∙h) than that from 600 rpm. In addition, when pH was controlled by 5.0, xylitol and ethanol concentration were increased, but cell growth was decreased. The optimum fermentation conditions were 500 rpm and pH 5.0 for ethanol production. Under the optimum conditions, xylose consumption rate, xylitol production rate and ethanol production rate were 1.05 g/L∙h, 0.43 g/L∙h and 0.13 g/L∙h, respectively.