A 1329 nucleotide long endoglucanase gene was amplified from marine bacterium Photobacterium panuliri strain LBS5(T).The enzyme sequence was novel as protein-based similarity search revealed that it shared maximum similarity of 99 % with hypothetical protein of P. aquae and 40 % with endoglucanase of P. marinum AK15. The gene was cloned, overexpressed in Escherichia coli BL21 (DE3), and purified up to homogeneity using Ni-NTA affinity chromatography. The purified enzyme, designated as Cel8, was monomeric and has a molecular mass of 53 kDa. The enzyme was halostable and exhibited optimal carboxymethyl cellulase (CMCase) activity and stability at 2 M NaCl. Optimal activity was obtained at 40 A degrees C and at pH 4. The enzyme exhibited remarkable stability in different organic solvents (50 %, v/v), and activity increased nearly 1.5-fold in presence of butanol, isopropanol, petroleum ether, benzene, acetone, and n-hexane. It was active in Ca2+, Ba2+, and Ni2+ and inhibited by Co2+, Cd2+, Zn2+, Cu2+, and Hg2+. Under normal physiological conditions, the enzyme has 25 % helix, 30 % sheets, and 56 % irregularities, whereas salt leads to helix to sheet transition in enzyme. Three-dimensional reconstruction analysis revealed that the enzyme has (alpha/beta)(8) structure and a TIM barrel fold-like structure at the central groove of enzyme. This is the first evidenced report on halostable, organic solvent tolerant cellulase in the marine bacterial genus Photobacterium.