Abstract
The cloned genes for thermostable xylan-degrading enzymes, xylanase and β-xylosidase, of Bacillus stearothermophilus No. 21 were found to have a unique clustered gene structure. From the cloned genes, the systems for simultaneous or individual expression of each enzyme gene in Escherichia coli were constructed. In these systems, each enzyme activity was efficiently expressed in E. coli several times over compared with that of B. stearothermophilus No. 21. The enzymes from each expression system were tested for the utilization for xylose- or xylobdose-selective producing systems from xylan.
