PERAN BAKTERI DALAM MENGUBAH ARSEN ANORGANIK MENJADI ARSEN ORGANIK DI PERAIRAN (The Roles of Bacteria in Modifying Inorganic Arsen to Organic Arsen in Waters)

Abstract

ABSTRAK

Tujuan penelitian ini adalah mengetahui peranan bakteri Esherichia coli dan Pseudomonas sp. dalam menubah spesies arsen. Arsenik dikenal sebagai salah satu unsur kimia yang mempunyai toksisitas tinggi. Analisis mentenai spesiasi arsen yang terkandung dalam perairan dilakukan dengan metode gabungan Kromatografi cair Kinerja Tinggi – Spektrometri Serapan Atom (HPLC-AAS). Untuk mengetahui peranan bakteri E.Coli dan Pseudomnonas sp. maka dilakukan tiga perlakuan, yaituperlakuan dengan variasi media pertumbuhan, variasi pH, dan variasi suhu inkubasi. Media pertumbuhan yant ditunakan yai5u air, l – metionin, nutrient broth, czapek dox, dan garam mineral. Variasi pH dilakukan pada pH 4, 5, 6, 7, 8, dan 9, sedangkan variasi suhu silakukan pada 25^oC sampai dengan 35^oC. Hasil penelitian menunjukkan bahwa ada peningkatan persentase jumlah As (V) yang terenduksi menjadi As (III) dalam media garam mineral pH7 dengan suhu optimum 35^oC. Enzim yang dihasilkan Pseudomonas sp. dapat mereduksi As (V) menjadi As (III) pada media garam mineral pH 8 dan optimum pada semua variasi suhu. Keseluruhan hasil penelitian menunjukkan bahwa bakteri E. coli dan Peseudomonas sp. dapat meningkatkan toksisitas arsen di perairan karena kedua bakteri dapat mereduksi As (V) menjadi As (III) pada pH dan temperatur optimum.

ABSTRACT

The aim of this research was to know the roles of Escharichia coli and Pseudomonas sp. in arsenic speciation. Arsenic has been known as highly toxic chemical element. The analysis towards arsenic speciation which is contained in waters was done by using High Pressure Liquid Chromatography (HPLC) – Atomic Absorption Spectrometry (AAS) coupling method. The observation towards the roles of E.coli and Pseudomonas.sp was done by variating the growth medium, pH and incubation temperature. The growth medium used in this observation were later, l – metionin, nutrient broth, czapek dox and mineral salt. The variation of pH was carried out at pH of 4,5,6,7,8, and 9. The variation of incubation temperatures was done from 25^oC to 35^oC. The result showed that there was increasing percentage of As (V) reduced to As (III) by E. coli in mineral salt medium pH of 7 and its optimum incubation temperature was 35^oC. The observation towards Pseudomonas sp. showed that the activity of enzyme produced from Pseudomonas sp. can reduce As (V) to As (III) optimum in mineral salt medium pH of 8 and in all variation of temperatures. The result above showed that E. coli and Pseudomonas sp. can increase the toxicity of arsenic in waters because both bacteria are able to reduce As (V) to As (III) carried out at pH and temperature of its growth