Judul: Analisis Komunitas Bakteri Fruktosfer Kelapa Sawit Menggunakan Teknik Terminal Restriction Fragment Length Polymorphism (T-RFLP)
Abstrak: The knowledge about bacterial community could provide basic information for the development of further research. One method that could be used to analize the diversity of microbial community is Terminal Restriction Fragment Length Polymorphism (T-RFLP). The objective of this research is to analyze the existing bacterial diversity on oil palm fructosphere. The 16S rRNA genes were amplified by PCR using forward primer (27F) and reverse primer (926R) which have been labeled. The PCR product were then digested with four different enzymes, namely BstUI, MspI, DdeI, and Sau96I. The elecroforegram showed that these enzymes produce different patterns due to the unique restriction sites of each enzymes. In general, BstUI and MspI enzymes produce more Terminal Restriction Fragment (TRF) than two other enzymes. From T-RFLP analysis we could identify some bacterial genus. Bacteria that were predicted to be present in oil palm fructosphere were gram-positive and gram-negative bacteria, Proteobacteria, Actinobacteria, soil bacteria, marine bacteria, and bacteria that could not be cultured.
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Judul: Penapisan Bakteri Lipolitik asal Fruktosfer Kelapa Sawit
Abstrak: Lipase (EC 3.1.1.3, glycerol ester hidrolase) is defined as carboxylesterase that catalyzes the hydrolysis of long chain asilgliserol. Lipase produced by lipolytic bacteria that grow well in substrates containing oils such as oil palm fruit. The purpose of this study was to screen lipolytic bacteria from oil palm fructosphere and to characterize optimal pH and temperature of lipase enzyme from selected isolates. Seven isolates of lipolytic bacteria with different morphology were qualitatively screened from oil palm fructosphere using Rhodamin B media. Bacteria were isolated from the exocarp and mesocarp of ripe oil palm fruits. Lipolytic activity each isolates were measured and selected based on their activity. Three isolates possessed the best activity with result as follows EP2.22 (0.912 U/mg), F2 (0.792 U/mg), and F6 (0.650 U/mg). These isolates showed high activity at various range of pH and temperature. Isolate EP2.22 showed optimum pH at 7.5 and optimum temperature at either 40 oC or 70 oC. Isolate F2 showed optimum pH 8.5 and optimum temperature 70 oC. Isolate F6 showed optimum pH 8.5 and optimum temperature at 30 oC and 70 oC. Two peaks of high activity due to the use of crude enzyme extract. 16S rRNA gene sequencing indicated that isolates EP2.22, F2, and F6 closely related to Staphylococcus klosii Enterobacter sp., and Buttiauxella izardii.
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Judul: Sintesis Superkonduktor YBa2Cu3O7-X Dengan Proses Pelelehan dan Karakterisasinya
Abstrak: Superkonduktor adalah bahan yang memiliki resistansi nol dan dapat melayang di atas magnet. Kedua sifat itu tampak pada saat bahan berada di bawah kondisi parameter kritisnya, yaitu batas kemampuan bahan tersebut dalam: menghantarkan arus tanpa resistansi (Jc) dan mempertahankan superkonduktifitasnya saat berada dalam medan magnet kritis (He) selain kedua parameter ini, superkonduktivitas juga dibatasi oleh suhu kritis (Te) yaitu kondisi suhu yang harus dipenuhi agar bahan dapat menampilkan kedua sifat tersebut. Karena itu penelitian superkonduktor umumnya ditujukan untuk meningkatkan ketiga parameter kritis tersebut, agar bahan ini dapat diaplikasikan seeara nyata. Dalam upaya meningkatkan parameter kritis bahan tersebut, pada penelitian ini dilakukan proses sintesis superkondu1.-tor dengan proses sintering yang kemudian dilanjutkan dengan proses pelelehan. Proses sintering merupakan proses yang telah umum digunakan, dan telah berhasil mendapatkan Te yang tinggi. Namun harga Jc yang diperoleh masih relatif rendah. Hal ini disebabkan karena produk superkonduktor yang dihasilkan melalni proses ini memiliki banyak sumber-sumber "weak link" berupa pori, celah dan cacat kristal lainnya serta mengandung fasa-fasa non-superkonduktif. Proses pelelehan bertujuan untuk mereduksi sumber-sumber "weak link" melalui proses grain alIignment dan mengendalikan kandungan fasa non-superkonduktif seperti fasa Y-211 sehingga harga Je dapat meningkat.
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