Isolation and Characterization of a Cold-Active Xylanase Enzyme from Flavobacterium sp.

Xylan is the major component of hemicellulose, and xylan should be fully utilized to improve the efficiencies of a biobased economy. There are a variety of industrial reaction conditions in which an active xylanase enzyme would be desired. As a result, xylanase enzymes with different activity profiles are of great interest. We isolated a xylanase gene (xyn10) from a Flavobacterium sp. whose sequence suggests that it is a glycosyl hydrolase family 10 member. The enzyme has a temperature optimum of 30°C, is active at cold temperatures, and is thermolabile. The enzyme has an apparent K_m of 1.8 mg/ml and k_cat of 100 sec⁻¹ for beechwood xylan, attacks highly branched native xylan substrates, and does not have activity against glucans.