Isolation and Characterization of a Novel Cold-Active, Halotolerant Endoxylanase from Echinicola rosea Sp. Nov. JL3085T

We cloned a xylanase gene (xynT) from marine bacterium Echinicola rosea sp. nov. JL3085(T) and recombinantly expressed it in Escherichia coli BL21. This gene encoded a polypeptide with 379 amino acid residues and a molecular weight of similar to 43 kDa. Its amino acid sequence shared 45.3% similarity with an endoxylanase from Cellvibrio mixtus that belongs to glycoside hydrolases family 10 (GH10). The XynT showed maximum activity at 40 degrees C and pH 7.0, and a maximum velocity of 62 mu moL min(-1) mg(-1). The XynT retained its maximum activity by more than 69%, 51%, and 26% at 10 degrees C, 5 degrees C, and 0 degrees C, respectively. It also exhibited the highest activity of 135% in the presence of 4 M NaCl and retained 76% of its activity after 24 h incubation with 4 M NaCl. This novel xylanase, XynT, is a cold-active and halotolerant enzyme that may have promising applications in drug, food, feed, and bioremediation industries.