Judul: Aplikasi Enzim Bakteri Selulotik dan Xilanolitik  Dalam Dekomposisi Substrat Limbah Tanaman Padi
Abstrak: The cellulolytic and xilanolytic bacteria are among organisms that is important to decompose organic matters from agriculture with higher lingo-cellulose compound such as rice straw. This research aims to isolate cellulolytic bacteria from agricultural soil in West and Central Java, and to study the cellulolytic and xilanolytic capacity of selected bacteria (45I-3 and 234P-16) to decompose rice straw. Method of this research comprised isolation and selection of cellulolytic bacteria which have a higher cellulolytic activity and was able to grow under higher temperature (50 oC). The selected bacteria than were analysed their ability to decompose rice straw for 6 weeks. Four combinations of bacteria including C4-4 + Xilanolytic (A), C5-1 + Xilanolytic (B), C11-1 + Xilanolytic (C), 45I-3 + 234P-16 (D), and control (without bacteria) were applied as inoculant of rice straw decomposition. The parameters analysed including the changes of pH-H2O, temperature, C-organic, total N and NNH4 +, decomposition rate, remaining weight, macro-micro nutrient content as well as physical properties of the substrate. There were 3 prospective isolates of cellulolytic bacteria resulted from the total of 31 isolates we found, i.e. C4-4, C5-1, and C11-1. The pH-H2O value of C4-4 + Xilanolytic (A) and C5-1 + Xilanolytic (B) was relatively more stable. C/N ratio of all treatments decreased after 3 weeks incubation. The C/N ratio value of A, B, C, D and E treatments were 22.484, 23.425, 27.494, 26.823, and 29.525 respectively. Decompositon rate all of combination A, B, C, D treatments were quicker than the control. The content of macro-micro nutrient of A, B, C, D treatments increased in the end of measuremant, while the control didn’t. The physical characteristic of substrate including the shape and colour was better in A and B treatments that others. The result indicated that the combination of C4-4 + Xilanolytic (A) and C5-1 + Xilanolytic (B) bacteria was the best combination of cellulolytic and xilanolytic bacteria for decomposition of rice straw.
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Judul: Potensi konsorsium isolat bakteri dekomposer dan penghasil IAA untuk memacu pertumbuhan kacang hijau
Abstrak: The agricultural product has increased rapidly, so it affects not only agricultural waste but also agricultural byproducts, such as straw and corn leaves. The agricultural byproducts can be utilized to be organic fertilizer. It needs microorganism to make organic fertilizer through decomposition process. One of this microorganism is cellulolitic bacteria. Cellulolitic bacteria that produced IAA can be used for composting and inducing plant growth. The objective of this research is to know the ability of isolate bacteria in decomposing organic matter and synthesing IAA to induce plant growth. Miller method was used to measure the activity of cellulase enzyme and Salkowski reagent was used to measure the IAA concentration of both single and consortium bacteria. The parameters of decomposition were the percentage of final weight, the percentage of C-organic, and the percentage of N-total. Biossay qualitative method was used to identify the presence of IAA in litter. Isolate K resulted the highest activity of cellulase enzyme with using CMC substrat and also had activity in avicel and filter paper substrat. Isolate C11-1 and C11-1+H+ K resulted the highest IAA concentration. The result of decomposition showed that isolate C11-1+H+K had the lowest percentage of final dry weight. The litter that decomposed with C11-1+H tended to induce plant growth higher than others, it might that this consortium have the certain IAA concentration to induce plant height.
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Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf