EXTRACTION OF NUTRIENTS FROM BROWN ALGAE (Sargassum SP.) USING AS ORGANIC FOLIAR FERTILIZER

Abstract

Brown alga (Sargassum sp.) is a source of materials used to extract fucoidan, alginate, and polysaccharide. In addition to alginate as the main ingredient, Sargassum sp. contains large amounts of macronutrients, medium and micronutrients and growth promoters such as olioalginate, laminarin, auxin, gibberellin, and cytokinin. Brown alga is also used as a source of plant nutrients. The research content of the study was investigation of optimum conditions in the extraction of nutrients from brown alga (Sargassum sp.), using as organic foliar fertilizer. Results of the study were obtained by extracting the macronutrients, medium and micronutrients from the seaweed in two stages: in the first stage, the brown alga was immersed in 24 hours with acid, then boiled for 1 hour, in the second stage, it was boiled for 1 hour with Na₂CO₃, mixing solution 1 and 2 at ratio of 1:1 to obtain the final solution and alginic acid. Results of the study also yielded appropriate acid solutions for the suitable concentration of 0.2-0.5 mol/L and Na₂CO₃ solution in the range of 0.1-0.25 mol/L; the suitable ratio of algae to solvent of 1:5. Besides, CH₃COOH and H₃PO₄ can be replaced by hydrochloric acid. The content of substances in the finished product solution included 71.4 mg/100 mL nitrogen, P₂O₅ 11.23 mg/100 mL, K₂O 1.21%, CaO 52.92 mg/100 mL, MgO 71.3 mg/100 mL, Fe 5.41 ppm, Zn 1.3 mg/100 mL, Mn 9.51 ppm.

Keywords: Alginate, brown alga (Sargassum sp.), organic foliar fertilizer, HCl, Na₂CO₃.