Judul: Identifikasi dan laju konsumsi metana Bakteri Metanotrof dari lahan sawah Indramayu dan Surabaya
Abstrak: Metana merupakan salah satu gas rumah kaca yang menyebabkan pemanasan global. Bakteri metanotrof memanfaatkan metana sebagai sumber karbon dan energi. Penelitian ini bertujuan mengisolasi bakteri metanotrof dan mengidentifikasi gen pengoksidasi gas metana. Tujuh isolat bakteri metanotrof (IM1, IM2, IM5, SB2, SB3, SB4, dan SB5) diisolasi dari tanah sawah melalui teknik pengayaan dengan media NMS (nitrate mineral salts). Pengukuran laju konsumsi metana dilakukan dengan kromatografi gas. Hasil penelitian menunjukkan bahwa ketujuh isolat mampu mengoksidasi gas metana. Laju konsumsi metana tertinggi dimiliki isolat SB3. Identifikasi gen yang mengkode enzim metana monooksigenase (pmoA) menggunakan primer yaitu A189f - mb661r menunjukkan IM2, IM5, SB2, SB3, SB4 dan SB5 memiliki gen pmoA. Hasil perunutan DNA gen pmoA dan analisis blast menunjukkan dua isolat masuk ke dalam genus Methylocystis dan empat isolat masuk ke dalam genus Mesthylosinus. Kedua gen tersebut masuk dalam kelompok metanotrof tipe II yang menggunakan jalur serin untuk mengoksidasi metana.
Keyword: methane, methanotrophic bacteria, pmoA gene

Judul: Identifikasi Bakteri Pengoksidasi Metana dan Gen Fungsional Isolat dari Tanah Sawah dan Gambut
Abstrak: Methane is one of green house gases. Methanotrophic bacteria can use methane as their carbon sources, therefore this bacteria has important role to reduce methane emission from soil and wet land. This research aim to isolate methane oxidizing bacteria and identify genes responsible for methane oxidation. Seven isolates of methanotrophic bacterias (AM1, AM2, AM3, AM4, AM5, AM6, dan AM7) were isolated from rice field and wet land through sub-culture in NMS (nitrate mineral salts) added by methane gases method. All of isolates could use 15 mL of methane gases at the third weeks of incubation and 0,7 mL per day in average. Identification of methane monooxygenase (pmoA) gene used two sets primer, 189f - 682r and 189f - 650r. The results showed isolates AM1, AM2, AM4, AM5, and AM6 had pmoA genes. All of the isolates also had functional methanol dehydrogenase (mxaF) gene. The result of 16S rRNA and blast analysis confirmed that six isolates were identified as Methylocystis and one isolate was Mesorhizobium. Phylogenetic analysis shows all strains would be novel species.
Keyword: pmoA gene., mxaF gene, Mesorhizobium, Methylocystis

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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