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: Karakterisasi Enzim Selulase dan Aplikasinya pada Substrat Limbah Pertanian
Abstrak: Cellulose is the most abundant plant cell walls. Lignocellulolytic are consist of cellulose, hemicelluloses and lignin. Degradation of cellulose involves a complex interplay between different cellulolytic enzymes. Among others, it has been widely accepted that three types of cellulases including endoglucanases, exoglucanases and β-glucosidases act synergistically to convert cellulose to glucose. This study was aimed to characterized cellulase enzyme which produced by cellulolytic bacteria from soil and applied it on agricultural waste such as rice straw, corn cob and banana peel. Qualitative analysis have done on 9 isolates cellulolytic bacteria to know the highest cellulolytic index by using congo red 0.1%. From 9 isolates, 1 isolate have IS 1.75. Quantitative analysis showed isolate 6-2 has the highest cellulase activity of 0.005U/ml. Highest activity of cellulase enzyme from isolate 6-2 resulted on bufer pH 7 and 40oC. Cellulase activity of isolate 6-2 was stable for 75 minutes. Isolate 6-2 has relatively low cellulase activities in CMC as it has small enzyme activity in degrading substrates of agriculture waste. The cellulose enzyme activity on ricestraw resulted 0.007U/ml, corncob resulted 0.008U/ml, and bananapeel resulted 0.013U/ml. Isolate 6-2, gram positive bacteria can degrade cellulose by using cellulase enzyme. On the application cellulase enzyme activity on bananapeel was higher than the others.
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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