초록
This work emphasizes the potential of the isolated Bacillus sp. lipase for the production of fatty acid methyl ester by the direct transesterification of Oedogonium sp. of macroalgae. Dimethyl carbonate was used as the extraction solvent and also as the reactant. The effect of solvent/algae ratio, water addition, catalyst, temperature, stirring and time on the direct transesterification was studied. The highest fatty acid methyl ester yield obtained under optimum conditions (5 g Oedogonium sp. powder, 7.5 ml of solvent (dimethyl carbonate)/g of algae, 8% catalyst (%wt/wt of oil), distilled water 1% (wt/wt of algae), 36 h, 55<SUP>o</SUP>C and 180 rpm) was 82%. Final product was subjected to thermogravimetric analysis and <SUP>1</SUP>H NMR analysis. The results showed that the isolated enzyme has good potential in catalyzing the direct transesterification of algae, and the dimethyl carbonate did not affect the activity of the isolated lipase.