Purification and enzymological characterization of xylanase from Erwinia dissociant.

The high-yield bacteria (Erwinia), which produced 408 U xylanase, was screened from 309 existing microorganism resources. Xylanase was purified under ultrafiltration and gel-filtration chromatography with a recovery yield of 69.17 % and specific activity of 28453.60 U/mL. The characterization of the xylanase was as follow: Its molecular mass was 22.54 and 21.89 kD by SDS-PAGE and gel-filtration chromatography, respectively. pI was 9.63 via IEF gel electrophoresis. Apparent Kmand Vmax values for oat-spelt xylan were 0.5 mg/mL and 533 U, respectively. It had an optimum pH of 5.8, and was stable over pH 3.4~6.4. The optimal temperature was 60 ℃ and it was stable over 0~65 ℃ at pH 5.8. And the activity was activated by Fe2+and Co2+, but was strongly inhibited by Cu2+. The partial amino acid sequence was consistented with the amino acid sequences on GenBank.