Xylan degradation by the thermophile Clostridium stercorarium: cloning and expression of xylanase, beta-D-xylosidase, and alpha-L-arabinofuranosidase genes in Escherichia coli.

Seven genes related to arabinoxylan degradation were isolated from a genomic library of the thermophilic bacterium Clostridium stercorarium. The cloned genes include a xylanase gene (xynA), two beta-D-xylosidase genes (bx1A and bx1B), two alpha-L-arabinofuranosidase genes (arfA and arfB), and two genes (celW and celX) encoding enzymes termed celloxylanases, which hydrolyze both xylans and beta-D-cellobiosides. The genes xynA, celX, and bxlB were found to encode the major xylanolytic enzyme activities induced by growth of C. stercorarium on xylan.