Purification and characterization of xylanases from Cellulomonas sp. N.C.I.M. 2353

• Published in: Biotechnology and applied biochemistry 1997-04, Vol.25 (2), p.127-133
• Main Authors: Chaudhary, Priya, Deobagkar, Dileep N.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Biology of microorganisms of confirmed or potential industrial interest; Biotechnology; Cellulomonas; Fundamental and applied biological sciences. Psychology; Miscellaneous; Mission oriented research
• ISSN: 0885-4513; 1470-8744
• DOI: 10.1111/j.1470-8744.1997.tb00424.x

Cellulomonas produces multiple xylanases in the presence of xylan, carboxymethylcellulose (CMC), starch and, to a very much lesser extent, cellobiose. A procedure involving (NH4)2SO4 precipitation, DEAE‐cellulose chromatography and gel filtration was used to purify the xylanases. True xylanases and xylanases with multiple specificity were detected. True xylanases had an optimum pH of 6.5, a temperature optimum of about 55 ° C, and pI values of about 8.0. The molecular masses of the purified xylanases were found to be 23, 33 and 53 kDa. The Km and Vmax values of the 33 and 53 kDa enzymes were 1.7 and 1.5 mg/ml, and 380 and 690 mmol/min per mg respectively. The 33 and 53 kDa enzymes were totally inactivated in the presence of HgCl2 and AgNO3. These two enzymes were not affected by 5 mM concentrations of KCl, MgCl2, NaCl and MnSO4. These enzymes were identified as endoxylanases on the basis of their end products. Xylanases other than these three enzymes were also found in a “cellulosome” type of complex in Cellulomonas. Enzymes in this complex showed activity towards both CMC and xylan.