원문정보
초록
영어
Kluyveromyces marxianus is well known thermotolerant yeast capable of growing at high temperature (45oC). However ethanol production is very inefficient from xylose which is second major sugar when cellulosic biomass is broken down enzymatically. Directed evolutionary approach and random mutagenesis were performed on K. marxianus KCTC17694 for isolating the mutant strain producing ethanol from xylose efficiently. The isolated mutant strain, K. marxianus 17694-DH1, exhibited 3.90 fold and 2.31 fold improvement in ethanol concentration and ethanol production yield from xylose, respectively as compared to the parental strain. When enzymatic assays of xylitol dehydrogenase (XDH) from the parental strain and K. marxianus 17694-DH1 were performed, XDH activities were significantly improved (28.1~64.8%) in the mutant strain up to 50°C of reaction temperatures. Under optimum conditions on bioreactor, xylose consumption rate and ethanol production rate were 0.66 g/L∙h and 0.14 g/L∙h, respectively which were 2.15 fold and 1.82 fold improvement, respectively as compared to those from the flask cultures.