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Purification and characterization of xylanases from Cellulomonas sp. N.C.I.M. 2353
Author(s) -
Chaudhary Priya,
Deobagkar Dileep N.
Publication year - 1997
Publication title -
biotechnology and applied biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.468
H-Index - 70
eISSN - 1470-8744
pISSN - 0885-4513
DOI - 10.1111/j.1470-8744.1997.tb00424.x
Subject(s) - xylan , cellobiose , enzyme , chemistry , size exclusion chromatography , cellulose , chromatography , biochemistry , cellulosome , starch , glycoside hydrolase , cellulase , clostridium thermocellum
Cellulomonas produces multiple xylanases in the presence of xylan, carboxymethylcellulose (CMC), starch and, to a very much lesser extent, cellobiose. A procedure involving (NH 4 ) 2 SO 4 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 K m and V max 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 HgCl 2 and AgNO 3 . These two enzymes were not affected by 5 mM concentrations of KCl, MgCl 2 , NaCl and MnSO 4 . 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.