Isolation of a Bacillus licheniformis DK42 Producing Cellulase and Xylanase, and Properties of the Enzymes
2008
Kim, M.J. (Dankook University, Cheonan, Republic of Korea) | Lim, S.J. (Dankook University, Cheonan, Republic of Korea) | Kang, D.K. (Dankook University, Cheonan, Republic of Korea), E-mail: [email protected]
A bacterium producing cold-active cellulase and xylanase was isolated from pig feces. The isolate, DK42 strain, was found to be the Gram-positive, non-motile, catalase-positive, and spore-forming stain. Under an electron microscope, the cells were observed to be rod-shaped. The isolate was identified as Bacillus licheniformis DK42 on the basis of morphological and biochemical properties as well as 16S rRNA gene sequences. The characterization of crude cellulase and xylanase from B. licheniformis DK42 was investigated. Cellulase exhibited an optimum temperature and pH at 45℃ and 6.0, whereas xylanase exhibited an optimum temperature and pH at 55℃ and 6.0. Especially cellulase maintained approx. 50% of its maximum activity even at 10℃, indicating that it is cold-active. Both cellulase and xylanase were stable after 2hr at 35℃, whereas they lost their activities after 30min at 65℃.
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