Carrageenan Content in Three Species of Hypnea ( H. musciformis Wulfen J. V. Lamouroux, H. pannosa J. Agardh and H. valentiae Turner Montagne) of Karachi Coast

Seaweeds are marine algae commonly found in marine environment. The red seaweed (Rhodophyta) is commonly exploited for the production of polysaccharides. Carrageenan is one of the commercial polysaccharide. It is complex of D-galactose 3, 6-anhydro D-galactose and monoesterified sulphuric acid found in cell wall of red seaweeds, used as an emulsifier, a binder. It is also used for suspension and stabilization in pharmaceutical, cosmetic and food processing. Hypnea is a red algal genus and well known carrageenan producing marine plant. Therefore three species of Hypnea : H. musciformis, H. pannosa and H. valentiae were collected from the four different coastal areas (Buleji, Hawks Bay, Manora and Paradise Point) of Karachi coast for the extraction of carrageenan in present study. The highest carrageenan extracted from H. valentiae (18-46.93%) as compared with the other two studied species. The high carrageenan concentration was mostly found in winter season. The total biomass 6846.79 g/m 2 of three species of Hypnea was recorded during the study period and the highest biomass was recorded in January and the lowest in August. The highest biomass was obtained from Manora coast as compared to other three coastal areas. There was significant correlation was found in between carrageenan and biomass. From the present investigation it is concluded that studied seaweeds species of Hypnea have good quantity of carrageenan and can be used in industries for the manufacturing and production of carrageenan.