Salinity Effects on Growth and Nutritional Content of Newly Isolated Microalgal with Potential Use in The Shrimp-Hatcheries

Abstract

A two-week batch experiment was conducted on three newly isolated Indonesian microalgal strains (Kb1-2 identified as Chaetoceros sp., Kb1-3 and Kb1-5) and Tisochrysis lutea to determine salinity effects upon the growth, proximate composition and ω-3, eicosapentaenoic acidand docosahexaenoic acid, (EPA and DHA) and ω-6 (arachidonic acid /ARA) fatty acids. Salinity within each strain growth of all microalgae tested. The highest cell densities were observed in Indonesian strains, Kb1-3 on day 8 at 25 psu and Kb1-5 on day 10 at 35 psu. Salinity significantly affected the lipid, protein and carbohydrate content in all microalgae cultured. The highest total lipid content was found in T. lutea cultured at 30 psu (28.3 %) followed by Kb1-2 cultured at 20 psu (25.0 %) and T. lutea at 35 psu (24.8 %). Kb1-3 produced highest protein when cultured at 20 and 25 psu, decreasing at higher salinities of 30 and 35 psu, 44.7 and 39.2 % to 31.5 and 32.6 %, respectively, similar to T. lutea. Kb1-5 had higher protein at both 25 and 35 psu but showed lower protein levels at 20 and 30 psu. Indonesian strains showed almost a similar content of carbohydrate across culture salinities similar to T. lutea. Although all Indonesian microalgae contained important ω-3 (EPA and DHA) and ω-6 (ARA) fatty acids, concentrations were low in comparison to T. lutea. All Indonesian microalgal strains also contained the dicarboxylic acid (DCA), phthalic acid, which was not present in T. lutea.