Abstract:
Salt stable cellulases are implicated in detritic food webs of marine invertebrates for their role in degradation of cellulosic material. A haloarchaeon, Haloferax sulfurifontis GUMFAZ2 producing cellulase was successfully isolated from marine Haliclona sp., a sponge inhabiting the rocky intertidal region of Anjuna, Goa. The culture produced extracellular xylanase-free cellulase with a maximum activity of 11.7 U/ml, using carboxymethylcellulose-Na (CMC-Na), as a sole source of carbon in 3.5 M NaCl containing medium, pH 7at 40 degrees C and produced cellobiose and glucose, detectable by thin layer chromatography. Native PAGE of the crude enzyme, revealed a single protein band of 19.6 kDa which on zymographic analysis exhibited cellulase activity while corresponding SDS?PAGE revealed a molecular weight of 46 kDa. Unlike conventional cellulases, this enzyme is active in presence of 5 M NaCl and does not have accompanying xylanase activity, hence can be considered as xylanase-free cellulase. Such enzymes from haloarchaea offer a great potential for biotechnological application because of their stability at high salinity and is therefore worth pursuing.
