Study On Purification And Charactcrization Of Xylanse From Erwinia Carotovora CXJZ11-01 Strain

We have studied the microbial strain resources by means of plate culture screening, single factor and multiple factor combinative methods, ultrafiltration concentration, and Sephadex G-100 gel chromatography methods. After a series of screening, a high-yield xylanase Erwinia strain was obtained. Furthermore, we have studied the optimal fermentation conditions,the enzymatic activity change curve of the strain.At last we have purificated the xylanase and studied the xylanase characteristics. We have obtained the purificated xylanase by electrophoresis. Consequently, our findings should have provided scientific basis for the industrialization and application of xylanase. The main results are as follow:1 We have screened a high-yielding xylanase Erwinia carotovora Strain, named CXJZ11-01.2 We have obtained the optimal growth medium and fermention medium.Use peptone as carbon source for strain CXJZ11-01, the xylanse peak is at 8.0 h, and reach 344U/ml.3 The optimal xylanase yielding determination conditions for CXJZ11-01 strain are: citric acid-sodium citrate buffer solution: 0.1 mol/L; pH value: 5.8; xylan substrate concentration: 0.8 %; temperature: 60℃; DNS dosage: 2.0~2.5 ml; DNS coloration time: 5min; determined wavelength: 540 nm.4 The optimal xylanase isolation conditions for CXJZ11-01 strain are: 50kD,10kD,5kD ultrafiltration concentration membrane and Sephadex G-100 gel chromatography methods. Results: the purification multiple and yield were 13.25 and 45.4%, respectively. Besides, a 29.3 kD of single band was obtained from SDS-PAGE.5 The enzymology characteristics of xylanase produced by CXJZ11-01 strain are: stable pH range from 3.4 to 6.4, action pH range from 4.0 to 7.0, with the optimal pH at 5.8. This kind of xylanase have a broad action temperature from 35℃to 60℃, and exhibite stable action effects below 60℃; Fe2+, Co2+ and Mn2+ observe to have activating effects on this xylanase, while Cu2+ exhibite inhibiting effects on it. Especially, enzyme activity lost 93 % when this xylanase was treated with 2mol/L of Cu2+ for 12 h.When the substrate was oat xylane, Km is 0.5 mg/L and Vmax is 33.31μmol/(min?ml).