Polyunsaturated fatty acids production by Schizochytrium sp. isolated from mangrove

Five Schizochytrium strains (N-1, N-2, N-5, N-6, and N-9) were isolated from fallen, senescent leaves of mangrove tree (Kandelia candel) in Hong Kong. The fungi were cultivated in glucose yeast extract medium containing 60 g of glucose, 10 g of yeast extract and 1 L of 15‰ artificial seawater, initial pH 6.0, with shaking for 52 hr at 25ºC. Biomass yields of 5 isolates ranged from 10.8 to 13.2 g/l. Isolate N-2 yielding the highest dried cell mass at 13.2 g/l and isolate N-9 grew poorly with 10.8 g/l of biomass. EPA (Eicosapentaenoic acid, 20:5n-3) yield was low in most strains, while DHA (Docosahexaenoic acid, 22:6n-3) was high on the same medium. The contents of DHA in biomass varied: 174.9, 203.6, 186.1, 171.3 and 157.9 mg/g of dried-biomass for Schizochytrium isolate N-1, N-2, N-5, N-6, and N-9, respectively. Isolate N-2 had the highest proportion of DHA in fatty acid profile with 15:0, 28.7%; 16:0, 21.3%; 18:0, 0.9%; 18:3, 0.2%; 20:4, 0.3%; 20:5, 0.9%; 22:4, 6.7%; 22:6, 36.1%; and others, 9.3%. The salinity range for growth of Schizochytrium isolates was from 0-30‰ with optimum salinity for growth between 20-30‰.