An endosymbiont Halobacterium salinarum MMD047, which could produce high yields of amylase, was isolated from marine sponge Fasciospongia cavemosa, collected from the peninsular coast of India. Maximum production of enzyme was obtained in minimal medium supplemented with 1 % sucrose. The enzyme was found to be produced constitutively even in the absence of starch. The optimum temperature and pH for the enzyme production was $40^{circ}C$ and 8.0, respectively. The enzyme exhibited maximum activity in pH range of 6-10 with an optimum pH of 9.0. The enzyme was stable at $40^{circ}C$ and the enzyme activity decreased dramatically above $50^{circ}C$. Based on the present findings, the enzyme was characterized as relatively heat sensitive and alkalophilic amylase which can be developed for extensive industrial applications.