Judul: Optimasi Aktivitas Selulase Ekstraseluler dari Isolat Bakteri RF-10
Abstrak: Cellulase is one of the enzymes used in many industrial applications. High enzyme price is the major problems faced in enzyme based industrial. One of the solution to decrease the enzyme price is to explore the potential microbe as producers of cellulase. This study aimed to determine the optimum incubation time for cellulase production of the RF-10 bacterial isolates and optimized optimum temperature and pH of cellulase. Cellulase activity of RF-10 bacterial isolate qualitatively was measured by Congo Red 0.1% staining method and quantitatively by 3.5-dinitrosalicylic acid method. The results showed that RF-10 produced cellulase based on clear zone formation and extracellular enzymes was obtained 1.625. The maximum cellulases production in CMC medium reached at the 42 hours with the activity 10.712 x 10-6 U/mL. Optimization of enzyme activity showed that the optimum temperature at 50 °C and optimum pH at 6.5. In addition, the enzyme has actively working in the range of pH 5.5-7.5.
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Judul: Isolasi dan Identifikasi Bakteri Termofilik Penghasil Selulase dari Kelapa Sawit (Elaeis guineensis)
Abstrak: Cellulase is an enzyme catalyzing hydrolysis of cellulose which usually consists of endoglucanases (EC.3.2.1.4), exoglucanases (EC.3.2.1.91) and β-glucosidases (EC.3.2.1.21). Cellulase is a very important enzyme due to its numerous industrial applications. The aim of this research were to isolate and identify cellulase-producing thermophilic bacteria that can be used to increase value added in oil palm industries. Samples of soil, empty fruit bunch compost and palm kernel meal were collected from oil palm plantation for obtained thermophilic bacteria. The samples were screened of cellulase-producing thermophilic bacteria by using a Congo Red method were made on carboxymethyl cellulose (CMC) agar plates. The bacterial cultures were incubated in a shaking incubator (140 rpm) at 50oC for 24 hours. The assay for the enzymatic activity was based on the release of glucose that was detected using 3,5-dinitrosalicylic acid (DNS). In this research, 19 isolates of bacteria were isolated. It was found that 11 isolates of bacteria showed positive results with clear zone around the cultures by using Congo Red method. The result showed that isolates for CK1, EM4 and CK3 possesed the highest enzyme activity of 13.56, 12.50 and 10.49 U mL-1 for cellulase was detected at pH 7, respectively. The results of strain identification based on 16S rRNA showed that strain CK1, EM4 and CK3 were identified as Bacillus subtilis.
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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