Sponges (phylum Porifera) are the oldest ancient metazoans which have existed for 700-800 million years.Most of them exist in marine environment and only a few (about 1%) of them inhabit in the freshwater.Marine sponges are also well known to be hosts for a large community of microorganisms,which comprise a significant percentage (up to 50-60%) of the biomass of the sponge host.The wide variety of microorganisms could play an important role in close associations with sponges,including nutrient acquisition,stabilization of sponge skeleton,processing of metabolic waste and secondary metabolite production.Recently,accumulating evidences indicate that the origin of bioactive compounds in marine sponges may be symbiotic microorganisms,or a cooperative interaction between sponges and associated microorganisms.