원문정보
초록
영어
Cellulase produced by Bacillus amyloliquefaciens DL-3 was purified by ammonium sulfate saturation of supernatant of culture broth after removal of cells and column chromatography through HiTrapTM QXL ion exchange column and Mono Q ion exchange column. The molecular weight of purified cellulase was estimated to be about 56 KDa by SDS-polyacrylamide gel electrophoresis. Optimal temperature and pH for the cellulase were determined to be 50℃ and
6.0, respectively. The cellulase was found to be stable between pH 6.0 and pH 9.0. The stability over a broad pH range seems to be characteristic of many Bacillus endoglucanases. Avicel, carboxymethyl cellulase (CMC) cellubiose, β -glucan and xylan as a substrate for the cellulase were tested. Among them, cellobiose were found to be the best substrate. Ca2+ ions increased the activity of the cellulase, while Hg2+, Co2+ and EDTA decreased the activity.
Michaelis-Mentens kinetics with Km and Vmax values were investigated. Km and Vmax values for hyrolysis of CMC were 0.92 ㎎/㎖ and 169.7 U/㎖ and those for hyrolytic reaction of p-nitrophenylglucose (pNPG) were 1.18 ㎎/㎖ and 25.56 U/㎖.