BETA-AGARASE FROM PSEUDOMONAS SP W7 - PURIFICATION OF THE RECOMBINANTENZYME FROM ESCHERICHIA-COLI AND THE EFFECTS OF SALT ON ITS ACTIVITY

The recombinant plasmid (pJAI), harbouring the agarase gene (pjaA) of Pseudomonas sp. W7, was introduced and expressed in Escherichia coli J M83. The agarase was purified using a combination of acetone precipita tion and anion-exchange, gel-filtration and affinity chromatographies, with overall yield of 10% from the culture supernatant of E. coli JM8 3 (pJAl), The purified agarase migrated as a single band (molecular ma ss 59 kDa) on SDS/PAGE and was found to be beta-agarase, which could h ydrolyse the beta-1,4 linkage of agarose to yield neoagarotetraose as the main product, Optimal enzyme activity was at pH 7.8 and the temper ature optimum spanned the broad range 20-40 degrees C, The recombinant agarase was halophilic, maximum activity being exhibited at 0.9 M NaC l. This halophilic property could improve the production of neoagaro-o ligosaccharides available in a marine environment.