Suksesi Mikroalgae pada insulasi dingin dan dinding luar tangki LNG/LPG :: Suatu pendekatan morfologis dan molekuar

JUARSIH, Juju, Dr.Ir. Irfan Dwidya Prijambada, M.Eng

2005 | Tesis | S2 Bioteknologi

Korosi pada peralatan logam industri gas bumi yang disebabkan oleh aktivitas mikroorganisme diawali dengan tumbuhnya mikroorganisme perintis yang kemudian diikuti oleh tumbuhnya jasad-jasad lain pada peralatan logam tersebut. Penelitian ini bertujuan untuk mengungkapkan proses suksesi mikroalgae yang tumbuh pada insulasi dingin dan dinding luar tangki LNG/LPG serta mengidentifikasi mikroalgae yang terlibat dalam proses tersebut. Penelitian dilaksanakan di PT Badak NGL Bontang Kalimantan Timur sejak bulan September-Desember 2003 kemudian dilanjutkan di laboratorium Mikrobiologi Pusat Studi Bioteknologi Universitas Gadjah Mada Yogyakarta. Penelitian ini menggunakan metode ekologi perubahan komunitas dengan petak sampling 1m2 kemudian dibiarkan sampai 8 minggu setelah dilakukan pembersihan. Pengambilan cuplikan dilakukan setiap dua minggu sekali sampai 4 kali pengambilan di 4 lokasi yang ditetapkan. Lokasi tersebut dipilih karena kondisi pertumbuhan mikroalgae paling banyak yaitu pada tangki bagian atas (dome), tangki bagian bawah yang basah (TBB), tangki bagian bawah yang kering (TBK) dan insulasi dingin. Mikroalgae yang diperoleh diidentifikasi berdasarkan pengamatan morfologi menurut Humm (1980). Analisis molekular untuk mengetahui komunitas mikroalgae dilakukan dengan menggunakan metode RISA (Ribosomal Intergenic Spacer Analysis). Pada minggu ke-2 setelah pembersihan, teramati beberapa macam mikroalgae, 4 genus di dome, 2 genus di TBB, 4 genus di TBK dan 3 genus di insulasi dingin. Pada minggu ke-4 setelah pembersihan, teramati 3 genus di dome, 2 genus di TBB, TBK dan insulasi dingin. Pada waktu pengamatan minggu ke-6 setelah pembersihan, teramati 3, 4, 1 dan 3 genus pada dome, TBB, TBK dan insulasi dingin. Pada akhir waktu pengamatan di minggu ke-8 setelah pembersihan, teramati 4, 4, 3 dan 4 genus pada dome, TBB, TBK dan insulasi dingin. Setelah diidentifikasi, diketahui bahwa mikroalgae yang tumbuh tersebut tergolong dalam genus Chroococcus, Lyngbya, Gloeocapsa, Oscillatoria, Gloeotrichia dan Trentepohlia. Analisis molekular menunjukkan beberapa macam pita DNA. Pada minggu ke- 2 setelah pembersihan teramati 4 pita di dome, 3 pita di TBB, 4 pita di TBK dan insulasi dingin. Pada minggu ke-4 setelah pembersihan teramati 3 pita di dome dan TBB, 2 pita di TBK dan 3 pita di insulasi dingin. Pada minggu ke-6 setelah pembersihan teramati 3 pita di dome,2 pita di TBB dan TBK serta 1 pita di insulasi dingin. Pada akhir waktu pengamatan di minggu ke-8 setelah pembersihan teramati 2 pita di dome dan TBB, 1 pita di TBK dan insulasi dingin. Hasil pengamatan morfologi dapat disimpulkan bahwa terjadi proses perubahan komunitas yang mengindikasikan terjadinya suksesi. Hal ini didukung oleh analisis molekular dengan menggunakan RISA sehingga diketahui pola perubahan pita DNA yang konvergensi pada setiap lokasi. Pengamatan secara morfologi dan molekular mengarah pada dugaan bahwa genus Gloeocapsa merupakan mikroalgae pionir dan dominan pada insulasi dingin dan dinding luar tangki LNG/LPG.

Corrosion on metal equipment of natural gas industries, which is caused by microorganism activity, is preceded by the growth of pioneer microorganisms and then followed by the growth of other organisms. The purposes of this research are to reveal microalgae succession process on cold insulation and the outer wall of LNG/LPG tank, as well as to identify the microalgae that involved in the process. The microalgae samples were obtained from PT Badak NGL Bontang, East Kalimantan. Microalgae isolation and identification were done in Laboratory of Microbiology, Center for Biotechnology Study, Gadjah Mada University. Samples were taken from four locations, i.e., upper tank (dome), wet lower tank, dry lower tank and cold insulation, which have the highest microalgae growth. Sampling was done using community change ecological method within 1 m2 plot. Sample plots were clean. The sampling were done every two weeks until two month. The obtained microalgae were identified based on morphological observation according to Humm (1980). Molecular analysis to detect the microalgae community was implemented by using RISA (Ribosomal Intergenic Spacer Analysis). Several kinds of microalgae were found two weeks after cleaning. There were found 4, 2, 4 and 3 genera respectively on dome, wet lower tank, dry lower tank and cold insulation. Four weeks after cleaning, on dome, wet lower tank, dry lower tank and cold insulation were found 3, 2, 2 and 2 genera respectively. Six weeks after cleaning, there were found 3, 4, 1 and 2 genera respectively on dome, wet lower tank, dry lower tank and cold insulation. In the end of the observation, eight weeks after cleaning, on dome, wet lower tank, dry lower tank and cold insulation were found 4, 4, 3 and 4 genera respectively. After identification, it was found that 61% microalgae not identified. Thirty nine percent microalgae were classified in to the genera of Chroococcus, Lyngbya, Gloeocapsa, Oscillatoria, Gloeotrichia and Trentepohlia. Molecular analysis shows that for some DNA bands. Several kinds of bands were identified two weeks after cleaning. There were found 4, 3, 4 and 4 bands respectively on dome, wet lower tank, dry lower tank and cold insulation. Four weeks after cleaning, on dome, wet lower tank, dry lower tank and cold insulation were found 3, 3, 2 and 3 bands respectively. Six weeks after the cleaning, there were found 3, 2, 2 and 1 bands respectively on dome, wet lower tank, dry lower tank and cold insulation. In the end of the observation, eight weeks after cleaning, on dome, wet lower tank, dry lower tank and cold insulation were found 2, 2, 1 and 1 bands respectively. Both morphological observation and molecular analysis indicate the occurrence microalgae succession. The genera of Gloeocapsa were found to be the pioneer microalgae which become dominant at the end of the observation at all sampling locations.

Kata Kunci : Bioteknologi, Suksesi Mikroalgae,corrosion, microalgae, succession, RISA.