Novel gene encoding xanthan lyase of Paenibacillus alginolyticus strain XL-1

Xanthan-modifying enzymes are powerful tools in studying structure-function relationships of this polysaccharide, One of these modifying enzymes is xa nthan lyase, which removes the terminal side chain residue of xanthan. In t his paper, the cloning and sequencing of the first xanthan lyase-encoding g ene is described, i.e., the xalA gene, encoding pyruvated mannose-specific xanthan lyase of Paenibacillus alginolyticus XL-1. The xalA gene encoded a 100,823-Da protein, including a 36-amino-acid signal sequence, The 96,887-D a mature enzyme could be expressed functionally in Escherichia coli, Like t he native enzyme, the recombinant enzyme showed no activity on depyruvated xanthan, Compared to production by P. alginolyticus, a 30-fold increase in volumetric productivity of soluble xanthan lyase was achieved by heterologo us production in E. coli. The recombinant xanthan lyase was used to produce modified xanthan, which showed a dramatic loss of the capacity to form gel s with locust bean gum.