Superoksida Dismutase Micrococcus sp.S2 :: Karakterisasi dan peran dalam Detoksikasi Paraquat

MAGDALENA, Medhina, Prof.Dr.Ir. Sebastian Margino

2005 | Tesis | S2 Bioteknologi

Paraquat merupakan bahan aktif herbisida dengan aksi menginduksi terbentuknya superoksida pada organisme. Micrococcus sp.S2 yang diisolasi dari gambut saprik, diketahui mampu mendegradasi paraquat, bahkan mampu tetap hidup hingga konsentrasi paraquat yang tinggi. Kemampuan hidup Micrococcus sp.S2 tersebut diduga terkait dengan aktivitas enzim superoksida dismutase (EC.1.15.1.1). Penelitian ini disusun untuk mempelajari peran superoksida dismutase dalam detoksikasi paraquat dan karakter enzim tersebut. Dalam penelitian ini yang dilakukan yaitu melihat pengaruh paraquat terhadap pertumbuhan Micrococcus sp.S2, dengan cara mengaplikasikan paraquat pada konsentrasi 0, 20, 40, 60, 80 dan100 (ppm), kemudian dilakukan pengamatan terhadap pertumbuhan bakteri secara turbidimetri, aktivitas enzim superoksida dismutase dan sisa paraquat pada medium. Pengamatan dilakukan pada jam ke-0, 12, 24, 36, 48, 60 dan 72. Untuk mengetahui karakter superoksida dismutase dilakukan uji penghambatan dengan inhibitor H2O2 dan KCN, kemudian dilakukan purifikasi superoksida dismutase dengan kromatografi penukar ion. Hasil penelitian menunjukkan, paraquat dapat menyebabkan penurunan jumlah Micrococcus sp.S2, semakin tinggi konsentrasi paraquat, penurunan jumlah bakteri semakin besar. Namun, Micrococcus sp.S2 mampu tetap hidup pada lingkungan yang mengandung paraquat, dan diduga karena aktivitas enzim superoksida dismutase. Micrococcus sp.S2 diketahui memiliki tiga isozim superoksida dismutase, yaitu Mn-SOD, Fe-SOD dan CuZn-SOD, dan diduga Mn-SOD berperan penting terhadap detoksikasi paraquat.

As an active ingredient of herbicide, redox cycling agent such as paraquat is a propagators of superoxide radicals inside organism’s cell. A former research succeeded in isolating bacteria from peat soil and discovered the ability of the paraquat degrading bacteria, Micrococcus sp.S2, to survive in an environment with high content of paraquat. An antioxidative enzyme, superoxide dismutase (EC.1.15.1.1), was believed to be responsible for this phenomena. This research was conducted to study about the character of superoxide dismutase from Micrococcus sp.S2 and its ability on scavenging superoxide which was arose as a consequence of paraquat reoxidation. To observe the effect of paraquat on Micrococcus sp.S2, the bacteria was grown in 10 % Luria Bertani broth supplemented with several dosage of paraquat, i.e. 0 (control), 20, 40, 60, 80 dan 100 (ppm, w/v). Bacterial growth, superoxide dismutase scavenger activity and paraquat residue were then monitored in particular incubation time, i.e. 0, 12, 24, 36, 48, 60 dan 72 (hours). The isozymes of superoxide dimutase were distinguished by using inhibitors H2O2 and KCN. Superoxide dismutase were then purified using ion exchanger chromatography system. Paraquat significantly causing decrease on Micrococcus sp.S2 growth. However, the bacteria still able to survive in the toxic environment, and this ability likely related to superoxide dismutase activity on removing superoxide from the environment. At least three isozymes of superoxide dismutase (SOD) discovered in this research, they were the Ferri-SOD (Fe-SOD), Mangani-SOD (Mn-SOD) and CuproZinc-SOD (CuZn-SOD). The Mangani-SOD was suspected to play an important role on removing superoxide which was arose because of paraquat.

Kata Kunci : Bioteknologi,Paraquat,Micrococcus spS2,Superoksida, Micrococcus sp.S2, paraquat, superoxide, superoxide dismutase