title: Characterization of Cellulolytic and Xylanolytic Enzymes of Bacillus licheniformis JK7 Isolated from the Rumen of a Native Korean Goat.
abstract: A facultative bacterium producing cellulolytic and hemicellulolytic enzymes was isolated from the rumen of a native Korean goat. The bacterium was identified as a Bacillus licheniformis on the basis of biochemical and morphological characteristics and 16S rDNA sequences, and has been designated Bacillus licheniformis JK7. Endoglucanase activities were higher than those of β-glucosidase and xylanase at all temperatures. Xylanase had the lowest activity among the three enzymes examined. The optimum temperature for the enzymes of Bacillus licheniformis JK7 was 70°C for endoglucanase (0.75 U/ml) and 50°C for β-glucosidase and xylanase (0.63 U/ml, 0.44 U/ml, respectively). All three enzymes were stable at a temperature range of 20 to 50°C. At 50°C, endoglucanse, β-glucosidase, and xylanase had 90.29, 94.80, and 88.69% residual activity, respectively. The optimal pH for the three enzymes was 5.0, at which their activity was 1.46, 1.10, and 1.08 U/ml, respectively. The activity of all three enzymes was stable in the pH range of 3.0 to 6.0. Endoglucanase activity was increased 113% by K(+), while K(+), Zn(+), and tween 20 enhanced β-glucosidase activity. Xylanase showed considerable activity even in presence of selected chemical additives, with the exception of Mn(2+) and Cu(2+). The broad range of optimum temperatures (20 to 40°C) and the stability under acidic pH (4 to 6) suggest that the cellulolytic enzymes of Bacillus licheniformis JK7 may be good candidates for use in the biofuel industry.
authors: Department of Agriculture Biotechnology, Research Institute for Agriculture and Life Sciences, College of Agriculture and Life Science, Seoul National University, Seoul 151-742, Korea.
authors: J K
authors: JK
authors: Seo
authors: Department of Agriculture Biotechnology, Research Institute for Agriculture and Life Sciences, College of Agriculture and Life Science, Seoul National University, Seoul 151-742, Korea.
authors: T S
authors: TS
authors: Park
authors: Department of Agriculture Biotechnology, Research Institute for Agriculture and Life Sciences, College of Agriculture and Life Science, Seoul National University, Seoul 151-742, Korea.
authors: I H
authors: IH
authors: Kwon
authors: Department of Agriculture Biotechnology, Research Institute for Agriculture and Life Sciences, College of Agriculture and Life Science, Seoul National University, Seoul 151-742, Korea.
authors: M Y
authors: MY
authors: Piao
authors: Department of Agriculture Biotechnology, Research Institute for Agriculture and Life Sciences, College of Agriculture and Life Science, Seoul National University, Seoul 151-742, Korea.
authors: C H
authors: CH
authors: Lee
authors: Department of Agriculture Biotechnology, Research Institute for Agriculture and Life Sciences, College of Agriculture and Life Science, Seoul National University, Seoul 151-742, Korea.
authors: Jong K
authors: JK
authors: Ha
keywords: Bacillus licheniformis; Endoglucanase; Goat; Xylanase; β-Glucosidase