Expression of Ruminococcus albus xylanase gene ( xynA) in Streptococcus bovis 12-U-1

The objective of this study was to ligate the xylanase gene A ( xynA) isolated from Ruminococcus albus 7 into the promoter and signal-peptide region of the lichenase [beta-(1,3-1,4)-glucanase] gene of Streptococcus bovis JB1. This fusion gene was inserted into the pSBE11 vector, and the resulting recombinant, plasmid pXA, was used to transform S. bovis 12-U-1 cells. The transformant, S. bovis 12UXA, secreted the xylanase, which was stable against freeze-thaw treatment and long-time incubation at 37 degrees C. The introduction of pXA and production of xylanase did not affect cell growth, and the xylanase produced degraded xylan from oat-spelt and birchwood.