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: The Construction of Greedy SVP LLL Algorithm
Abstrak: A lattice is a set of all integer linear combination of a set of linearly independent vectors in ℝ𝑛���. The independent vectors are called bases of lattice. Any lattice can be generated from many bases, and these bases have the same cardinality. In the lattice, the most fundamental and renowned problem is the Shortest Vector Problem (SVP). SVP is a tracking problem of the shortest nonzero vector in a lattice with equivalent bases. In two dimensions, SVP problem has resolved exactly by Gauss’ algorithm. When the lattice dimension is higher than two, A.K. Lenstra, H.W. Lenstra and L. Lovasz gave a LLL algorithm to compute approximation of nonzero shortest vector in the lattice. Reduced bases solution obtained from LLL algorithm still be an approximation and has polynomial running time of arbitrary dimension which large enough. In 1994, Schnoor and Euchner modified this LLL algorithm as a new variant which later was named deep insertion LLL algorithm. This algorithm is a modified version of the LLL algorithm to the terms of the exchange step to improve the accuracy of output of LLL reduced bases and applying it to the subset sum problem. The purpose of this research are: (1) Reconstruct the LLL algorithm and deep insertion LLL algorithm using a geometric approach. (2) Construct a greedy SVP LLL algorithm. (3) Implement the three algorithms in a symbolic programming language, and evaluate them experimentally. A bases ℬ=[𝐛���1,𝐛���2,…,𝐛���𝑛���] in ℝ𝑚��� is called reduced LLL with parameter 𝛿��� if satisfies: (a) |𝜇���𝑗���𝑖���|≤12, for every integer 𝑖���,𝑗��� with 1≤𝑖���<𝑗���<𝑛���. (b)𝛿���‖𝜋���𝑗���(𝐛���𝑗���)‖2≤‖𝜋���𝑗���(𝐛���𝑗���+1)‖2, for 𝑗���=1,2,…,𝑛���−1,where 𝛿��� is a reduced parameter of real numbers with 14<𝛿���<1. The first requirement is the reduced basis 𝛿��� must “nearly orthogonal” and in its computation case, this requirement can be reached out by using the Gram-Schmidt’s orthogonalization. While the second requirement is called exchange step, or used to called as Lovasz condition. By using both of these requirements, then they establish the LLL algorithm. Then, Schnoor and Euchner modify the LLL algorithm based on the requirements of the exchange step called the deep insertion LLL algorithm, where the exchange step is based on the comparison of the projected vector in orthogonal complement [𝐛���1,𝐛���2,…,𝐛���𝑘���−1]⊥ after j-th reduction. To construct greedy SVP LLL algorithm, the requirements of the exchange step is based on purely by comparing norm of lattice 𝐛���𝑗��� with norm lattice 𝐛���𝑖��� for 𝑖���=1,2,3…,𝑗���−1. The process of insertion reduced vector after the exchange step also has done greedily. Then, we calculate the number of arithmetic operation in greedy SVP LLL algorithm for further analysis. The result of our exprimentation for three algorithms on the certain matrix size shows that the running time of the three algorithms increases propotional to the size of the matrix. The result also shows that by using 𝛿���=34 for the LLL algorithm and the deep insertion LLL algorithm, and the greedy SVP LLL algorithm which is a new variant made by using no parameter of 𝛿���, outperform of the other of two previous algorithm in terms of speed with the same output.
Keyword: LLL algorithm, LLL deep insertion algorithm, greedy SVP LLL algorithm