A novel biochemical study on carboxymethyl cellulase (endo-1,4-ß-D-glucanase) produced by Enterobacter cloacae isolated from soil

الملخص

     10 Enterobacter cloacae isolates were obtained out of 35 soil samples from different locations in the farms of kanat of army / east of Baghdad city .                                       

     The carboxymethyl cellulase  production condition by  Enterobacter cloacae  were studed ,the  Carboxymethyl CM medium was the best medium for production  of carboxymethyl cellulose CMCase  (endoglucanase)   with 5% of bacterial cells /ml ,Ph 7.5 and incubated at 35cº in shaking incubater  for 18-24 hrs.                                                              The isolate that gave higher cellulolytic activity was chosen to purify endoglucanase through four stages of purification including (ammonium sulfate precipitation, anion-exchange chromatography by DEAE-Sepharose, gel filtration chromatography by Sephadex G-150 and hydrophobic chromatography by phenyl- Sepharose   with 440U/mg specific activity, 29.3-fold purification and 31% recovery.                                                                                                                                 

   The purified carboxymethyl cellulase was characterized: the molecular weight was about 38 kDa by gel filtration chromatography. The temperature for maximum activity was 35°C and maximal activity was observed between pH 6.5 and 7.0. The enzyme showed higher activity on carboxymethel cellulose (CMC) with much lower activity on glucan. Cellotriose and cellobiose were not degraded and at least four catiguous glucosyl residues were necessory for degradation by the enzyme.