Microbial Production Of Ω3 Polyunsaturated Fatty Acid By Mangrove Derived Nannochloropsis Granulata
Omega-3 fatty acids, which are essential fatty acids, are necessary for human health. Microbial sources of Polyunsaturated fatty acids (PUFA) are currently being used in infant formula, for pregnant and nursing women, adult dietary supplements, as a food additive, and for cardiovascular health . The pharmaceutical importance of Docosahexaenoic acid (DHA) and the limitations of its traditional source have led to the exploitation of other alternative sources. Coastal marine environments are ecologically and biologically the most diverse. In the present study four isolates were isolated from the roots of mangrove tree. They were screened and cultured in view of their potential for the production of DHA in flask cultures. Biomass yields of four isolates ranged from 6.5 to 17.5 g/l. Isolate yielding the highest dried cell mass at 17.5 g/l was chosen for further study and identified as Nannochloropsis granulata. It was cultured under laboratory conditions in different media compositions and its biomass was harvested after specific incubation period. The biomass was prepared for fatty acid methyl ester (FAME) analysis using Gas Chromatograph. DHA production was tested in the biomass of this species at culturing conditions of pH 7.0, salinity of 25.00 ppt and temperature of 30°C for 7days. Nannochloropsis granulata contained a large proportion of DHA in total fatty acids (21.6 % w/w) and produced the highest yield of DHA (77.6 mg/1) among the four strains. High concentrations of glucose favored both biomass and omega-3 polyunsaturated fatty acid production. Medium composition had significant effects on both the growth and DHA production of this strain. This study found Nannochloropsis granulata as a promising strain for DHA production that can be stimulated under optimal growth conditions. Further studies on gene expression of genes encoding enzymes participating in fatty acid synthesis on species with high fatty acid contents such as Nannochloropsis granulate under optimal growth conditions can give a better comprehension of how to trigger and enhance the DHA synthesis.
Keywords - Docosahexaenic acid, Fatty acid methyl ester, Mangroves