LAUSR

Salt stable cellulases are implicated in detritic food webs of marine invertebrates for their role in the 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 7 at 40°C and produced cellobiose and glucose, detectable by thin‐layer chromatography. Nondenaturing polyacrylamide gel electrophoresis of the crude enzyme, revealed a single protein band of 19.6 kDa which on zymographic analysis exhibited cellulase activity while corresponding sodium dodecyl sulfate polyacrylamide gel electrophoresis 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 great potential for biotechnological application because of their stability at high salinity and is therefore worth pursuing.