PURIFICATION OF BETA-N-ACETYL-D-GLUCOSAMINIDASE FROM ASPERGILLUS-NIGER USING THERMOSTABILIZATION AND HEAT AS THE INITIAL STEP

A beta-N-acetyl-D-glucosaminidase (EG 3.2.1.30) produced by Aspergillu s niger 419, was completely inactivated after heating 15 min at 65 deg rees C in 100 mM sodium phosphate buffer pH 7. The presence of 10% of polypropyleneglycol 1025 induced the thermal stability of the enzyme, the activity remaining unchanged after heating 60 min at 65 degrees C. When this thermal treatment was used as the initial step of purificat ion, the protein content of the crude extract was reduced by 98% witho ut loss of the total initial enzymatic activity of the sample and a pu rification factor of 61. As the second and third step of purification DEAE-Sephacel, and Sephadex-G150 column chromatography were used, resp ectively. The final purification factor was 230 with a yield of 76%.