Kemampuan Bradyrhizohium Japonicum Menguraikan Beberapa Senyawa Aromatik

Abstract

The aromatic compounds in soil can be used as carbon and energy sources for bacterial growth. BradyrhizobiulIl japolliculIl was able to degrade aromatic compounds because they have a B-ketoadipic route. This research was conducted to study the ability of B. japoniculIl (Bj) sirains in degrading some aromatic compounds. In the qualitative test, Bj strains were grown on synthetic agar media supplemented by 1 roM aromatic compound. Translucent halo around the colony was observed and measured on day-4. A quantitative test were performed by growing Bj strains on synthetic liquid culture supplemented by ] mM aromatic compound and 4.8 mM sodium glutamate. Optical density (00) was measured at )" 608 nm on every other days for 16 days, and pH fluctuation was observed at day-8 and day-16. To get aromatic compound residual, cultures were acidified to pH 1.0 at day-8 and day-I 6, and subsequently extracted. The extract was measured by visible-ultraviolet spectrophotometer at )" 249 nm (for parahydroxybenzoic acid) and at )" 253 (for protocathecuic and gentisic acids). The ability to degrade aromatic compounds qualitatively were showed by strains II, 38, 50, 33, 49, and 09 respectively. Gentisic acid was the compound that showed translucent halo for Bj II (10.5 mm), followed by parahydroxybenzoic acid for Bj 38 (3.5 mm), protocathecuic acid for Bj 33 (2.8 111m), and vanillic acid for Bj II and 33 (2 mm). The highest 00 during day-4 was obtained by strain 49 (protocathecuic acid) and strain 33 (parahydroxybenzoic acid). The highest pH final was showed by strain 33 (8.78) for protocathecuic, strain 38 (8.34) for parahydroxybenzoic, and strain 38 (8.76) for gentisic. The lowest aromatic compound residue was shown by strain 33 (0.016) for protocathecuic, strain 38 (0.066) for parahydroxybenzoic, strains 33 and 49 (0.056 and 0.051 respectively) for gentisic. According to the growth, pH media, and aromatic compound residual, the strains that show a better performance are strains 33 and 49 for protocathecuic, strains 33 and 38 for parahydroxybenzoic, strains 38 and 49 for gentisic acid.