Judul: Methane oxidation activity of methanotrophic bacteria from ricefields under different consentration of oxygen
Abstrak: Methane-oxidizing bacteria (methanotrophs) have ability to oxidize methane to carbon dioxide via methanol, formaldehyde, and format in aerobic condition. Methanotrophic bacteria are normally abundant where methane is present. In aerobic environment, methanotrophic bacteria oxidize methane to provide carbon and energy for their growth. Methanotrophic bacteria have an unique enzyme known as methane mono oxygenase (MMO) catalizing reaction of CH4 and O2 to methanol. Three selected isolates from rice fields in Bogor and Sukabumi were tested the growth and methane oxidation activity under different concentration of oxygen (02) using Nitrat Medium Salts (NMS) medium. Methane oxidation rate ofBGM 9 isolate at 0%,10%, 20% and 50% air saturation was 129182.06 mol/day, 138185.16 mol/day, 137484.32 mol/day, 167015,88 mol/day respectively. In contl:ast, high rates of Methane oxidation were performed by BGM 2 and SKM 14 isolates at air saturation of 10% and 20%. However the activity was decreased at 50% air saturation.
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Judul: Growth and Methane Oxidation Activity of Methanotrophic Bacteria in Different Media
Abstrak: Methanotrophs are bacteria that can utilize methane or C1 compounds as their sole carbon and energy source. Previous study resulted that BGM 1, BGM 3, BGM 9, and SKM 14 isolates could oxidized CH4. Objective of this research was to formulate medium composition for production of methanotrophic bacteria. The substances that we used as carbon sources were methanol, mollase. And a nitrate was as a nitrogen source. Specific growth rate of bacteria in methanol and nitrate was different for each isolate. The best carbon and nitrogen sources of medium for bacterial growth was methanol 2% and nitrate 1 g/L. Methane oxidation rate of BGM 1, BGM 3, BGM 9, and SKM 14 isolates was 0.01, 0.04, 0.03, and 0.03 mol/ml culture/day respectively. The highest activity of methane oxidation was perfomed by BGM 3 isolate, and the highest ammonium accumulation was perfomed by BGM 9 isolate. The bacterial cells produced by medium of combination methanol 2% and nitrate 1 g/L were tested in soil of a rice field in laboratorium scale. The result showed that methane concentration was decreased in twelveth days of incubation. The methane reduction activity of the isolates during incubation of 8 to 12 days was 88.5%, 85.1%, 47.8%, and 66.4% for BGM 1, BGM 3, BGM 9, and SKM 14 isolates respectively.
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Judul: Penetapan Harga Jaminan Polis Asuransi Jiwa dengan Premi  Tahunan dan Opsi Surrender
Abstrak: Asuransi jiwa memberikan perlindungan pada tertanggung (pemegang polis) jika mengalami risiko finansial, dengan suatu perjanjian tertanggung harus membayar premi. Premi yang sudah terkumpul pada perusahaan asuransi dapat diinvestasikan, yang salah satu tempatnya adalah di pasar bursa. Perusahaan asuransi menawarkan suatu kontrak kepada pemegang polis yang disebut dengan kontrak partisipasi. Pada kontrak partisipasi risiko finansial dan keuntungan dibagi dengan pemegang polis dan biasanya keuntungan tersebut dimasukkan ke dalam cadangan polis pada tiap akhir tahun kontrak. Hal ini berarti secara tidak langsung perusahaan asuransi menyatakan penambahan pertanggungan, sehingga mengakibatkan perubahan benefit yang diterima oleh pemegang polis. Pada kontrak partisipasi ini, pemegang polis diberikan hak untuk mengakhiri kontrak (opsi surrender). Pada kontrak partisipasi asuransi jiwa endowmen terdapat opsi bonus (bonus option) yang penghitungan besar preminya dengan pendekatan tipe Eropa dan opsi surrender (surrender option) dengan tipe Amerika.
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