Biodegradasi herbisida kalium-2-metil-4-klorofenoksi asetat formula oleh bakteri

NURHAYATI, Prof.Dra. A. Endang Soetariningsih Soetarto, MSc.,PhD

2001 | Tesis | S2 Bioteknologi

Kalium-2-metil-4-klorofenoksiasetat formula (KMCPA formula) merupakan herbisida, komponennya persisten di alam. Hanya beberapa mikrobia yang mampu mendegradasi KMCPA formula dan menggunakannya sebagai sumber karbon dan energi. Penelitian ini bertujuan untuk mengisolasi bakteri indigenous pengguna KMCPA formula dengan teknik kultur diperkaya, mempelajari kemampuan tumbuh dan dehalogenasi bakteri yang ditumbuhkan pada berbagai konsentrasi KMCPA formula. Penelitian diawali dengan mengisolasi bakteri melalui teknik kultur diperkaya menggunakan KMCPA formula sebagai sumber karbon dan energi. Seleksi dan skrining isolat bakteri dehalogenasi diuji kemampuan tumbuhnya pada medium cair yang berisi : SBS + 1,l g/l KMCPA formula + yeast extract 0,05% (w/v); SBS + 2,2 g/l KMCPA formula + yeust extruct 0,05% (w/v); SBS + 3,3 g/l KMCPA formula + yeust extruct 0,05% (w/v). Pertumbuhan dimonitor secara spektrofotometer pada panjang gelombang 600 nm dan vruble pluting count. Isolat yang memiliki waktu generasi pendek dan kemampuan melepas CI- tinggi dipilih dan digunakan lebih lanjut. Pelepasan klor diukur dengan Chlorocounter. Kadar KMCPA formula diukur dengan High Performunce Liquid Chromatogruphy (HPLC). Bakteri yang diisolasi adalah bakteri mdrgenous strain M3. Laju pertumbuhan spesifik bakteri (p) : 0,1441/jam, waktu generasi (g) : 4,87 jam dan memiliki kemampuan menggunakan KMCPA formula sampai 3,3 8/1 dengan (p) O,1447/jam konstanta kejenuhan subtrat (Ks) : 0,OO 14 g/1 pada pH : 7 dan suhu 37" C, bakteri strain M3 merupakan bakteri yang banyak terdapat di tanah. Isolat mampu tumbuh dan menggunakan KMCPA pada konsentrasi 1,l g/l; 2,2 g/l; 3,3 g/1 dan melepas kurang lebih 74 mg/l, 54 mg/l dan 48 mg/l C1- per C1 total dalam medium dan memiliki kemampuan mendegradasi KMCPA formula pada konsentrasi 1,l gA selama waktu inkubasi 72 jam sebesar 90,6 1 % dengan degrudution time (DT50): 3 0,44 jam.

Potassium-4-chloro-2-methyl phenoxyacetic formula (KMCPA formula) is a herbicide, the component persistent in the environmeni. Some microbe are able degrade KMCPA formula and use a carbon and energy source. The aim of this research were to isolate indigenous bacteria by enrichment culture technique and to study the ability of growth and ability of dehalogenating bacteria in using KMCPA formula. The experiment was commenced with isolation of bacteria through enrichment culture technique using KMCPA formula as a sole carbon source. The selection and screening of dehalogenating bacterial isolated were carried out through growth experiments on to liquid media containing (SBS + 1.1 g/l KMCPA formula + yeast extract 0.05% (w/v); SBS + 2.2 gA KMCPA formula + yeast extract 0.05% (w/v); SBS + 3.3 g/l KMCPA formula + yeast extract 0.05% (w/v)). The growth was monitored spectrophotometrically at wavelengh 600 nm and by viable plating count. The isolates that had a short generation time and released high of CI- were selected and used for further experiment. Chlor release was measured by chlorocounter. Residue KMCPA was measured by high performance liquid chromatography. The bacteria isolated was designated Mg strain bacteria. Analysis demonstrated that the M3 strain bacteria was capable of growing and using KMCPA formula containing 1.1 gA; 2.2 @I; 3.3 g/l KMCPA fromula as a carbon and energy sources and released about 74 mg/l; 54 mdl; 48 mgA C1- per CI total in medium. The specific growth rate (p) in yeast extract supplemented medium was : O.l441/h, generation time (8) : 4.8 h in 1.1 s/l KMCPA formula and the spesific growth rate (p) : 0,1447k, generation time (g) : 4.87 h ,Ks : 0.0014 g/l in 3.3 g/l KMCPA formula. It was also calculated that the M3 strain was able to degrade KMCPA formula 90.61 % at DT5o level of30.44 h.

Kata Kunci : Biodegradasi Herbisida KMCPA Formula, Bakteri Indigenous