Isolasi dan Karakterisasi Bakteri Pendegradasi Pestisida Propoxur

Abstract

Propoxur merupakan bahan aktif insektisida dari kelompok karbamat non sistemik, yang biasanya digunakan untuk mengendalikan hama serangga. Pestisida propoxur banyak dipakai oleh masyarakat Indonesia dan berpotensi mencemari lingkungan. Upaya penanggulangan dampak negatif pencemaran pestisida propoxur salah satunya dapat dilakukan dengan bioremediasi melalui bakteri. Tujuan penelitian ini adalah melakukan isolasi dan karakterisasi isolat bakteri potensial pendegradasi pestisida berbahan aktif propoxur. Sampel sebagai sumber isolat berupa cairan dan endapan diambil dari tempat pengolahan limbah PT. Great Giant Pineapple, Lampung yang menampung air limbah proses perendaman bibit. Sampel diambil secara acak di lima titik kolam pengolahan limbah yang kemudian dikomposit dan ditampung pada jerigen berukuran 5 liter. Penelitian dilaksanakan di Kelompok Riset Mikrobioma Nutrisi Tanaman Pusat Riset Mikrobiologi Terapan-BRIN Cibinong, Jawa Barat. Penelitian dimulai pada bulan Januari 2022 hingga Maret 2023. Isolasi bakteri pendegradasi pestisida propoxur dilakukan dengan metode kultur yang telah diperkaya bahan aktif propoxur. Isolat yang tumbuh diseleksi berdasarkan penampakan koloni dan kemampuan tumbuh pada konsentrasi propoxur yang berbeda selanjutnya dilakukan pengamatan karakteristik morfologi dan fisiologi. Isolat yang terpilih diuji untuk mendegradasi propoxur secara kunatitatif. Selanjutnya isolat potensial terpilih diidentifikasi molekuler berdasarkan sekuens 16S rRNA dan dikarakterisasi pH serta suhu optimum pertumbuhannya . Hasil isolasi diperoleh enam isolat bakteri yang mampu tumbuh dalam media yang diperkaya propoxur 100, 300 dan 500 ppm dan dipilih satu isolat potensial yang memiliki kemampuan tumbuh paling baik pada media yang diperkaya bahan aktif propoxur yaitu isolat LED 6. Hasil analisis sekuens 16S rRNA isolat LED 6 adalah Brucella pseudintermedia (Ochrobactrum pseudintermedium). Dari karakterisasi pertumbuhan diketahui bakteri dapat tumbuh secara optimum pada lingkungan dengan suhu 28° C dan pada media pH 7. Isolat terpilih yang diinkubasikan pada media mineral yang mengandung propoxur selama 72 jam dan mampu merombak sekitar 26 % dari konsentrasi awal propoxur 500 ppm. Hal tersebut menunjukkan bahwa isolat bakteri Brucella pseudintermedia mampu tumbuh dengan menggunakan propoxur sebagai sumber karbon dan berpotensi sebagai agen bioremediasi pada pencemaran propoxur.

Propoxur is an insecticide active ingredient from the non-systemic carbamate group, usually used to control insect pests. Indonesians widely use the pesticide propoxur, which can potentially damage the environment. One of the efforts to overcome the negative impacts caused by propoxur pesticide residues is bioremediation through bacteria. This research was aimed to isolate and characterized potential bacterial isolates that degraded pesticides containing the active ingredient propoxur. The samples, carefully collected from liquids and waste processing sludge at PT. Great Giant Pineapple Lampung, were taken randomly at five waste processing pond, then composited and stored in 5-liter jerry cans. The research was conducted at the Plant Nutrition Microbiome Research Group, Applied Microbiology Research Center-BRIN Cibinong, West Java, from January 2022 to March 2023. The propoxur pesticide-degrading bacteria were isolated using a culture method enriched with propoxur. Isolates that grew were selected based on colony appearance and ability to grow at different propoxur concentrations, and morphological and physiological characteristics were observed. The selected isolates were tested to degrade propoxur quantitatively. Next, the potentially selected isolates were subjected to molecular identification based on the 16S rRNA sequence, and their pH and optimum growth temperature were characterized. The isolation results showed that six bacterial isolates could grow in media enriched with 100, 300, and 500 ppm propoxur. One potential isolate was selected which had the best ability to grow in media enriched with the active ingredient propoxur, namely LED 6. The 16S rRNA sequence analysis results for LED 6 were Brucella pseudintermedia (Ochrobactrum pseudintermedium). The growth characterization showed that bacteria can grow optimally at 28° C and a pH 7 medium. Selected isolates incubated in mineral media with propoxur for 72 hours could degrade around 26% of the initial propoxur concentration of 500 ppm. This shows that the Brucella pseudintermedia bacterial isolate can grow using propoxur as a carbon source and has the potential as a bioremediation agent for propoxur contamination.