Judul: Karakter Selulase Bakteri Isolat 26 Asal Tanah Hutan Taman Nasional Bukit Duabelas, Jambi, Indonesia
Abstrak: Indonesia is a country that has developed rapidly in the agricultural sector, which generated agricultural waste and it can be degraded into more useful materials by using microorganisms, such as bacteria. Isolate 26 origins from Bukit Duabelas National Park, Jambi alleged to have cellulase which is able to degrade cellulose into simple molecules. This study aimed to characterize isolate 26 which included the optimum of pH and temperature, for enzime activity as well as the appropriate substrates. Determination of cellulase enzyme activity of crude extracts performed at the optimum production of cellulase enzymes by modification of Miller (1959) method on the substrate CMC and filter paper, and applied to rice straw, corn cobs and banana peels. Optimum production of crude enzyme extract obtained from the 4th hour incubation period that is equal to 5.25 mU/mL with protein content of 0.102 mg/ mL. Cellulase from isolate 26 had an optimum activity at pH 4.5 and a temperature of 90OC. Compared to other substrates cellulase from bacterial isolate 26 had the highest ability to degrade on the banana peels.
Keyword: Bogor Agricultural University (IPB), cellulase., agricultural waste, characterization, cellulolytic bacteria

Judul: Isolasi dan Pencirian Xilanase dari Bakteri Asal Tanah Hutan Taman Nasional Bukit Duabelas, Jambi, Indonesia
Abstrak: Xylanase is a xylan-degrading enzymes which are useful to improving the bioconversion of lignocellulosic biomass into useful products. Broad application of xylanase have not optimized due to the lack of superior microbes. The aim of this study is to isolate bacterial origin Bukit Duabelas National Park, Jambi and characterize its xylanase, including its pH optimum, temperature optimum, and stability. A total of 28 potential isolates have been isolated from Bukit Duabelas National Park soil, Jambi and three were successfully characterized its xilanase (isolates 10, 18, and 27). Isolate 10 reached the highest producing extracellular xylanase at 12th and 36th hours of culture incubation with optimum activity at pH 6, temperature 40 °C and 90 oC. Isolate 27 reached its highest producing extracellular xylanase at 12th and 30th hours of culture incubation. The optimum condition of xylanase isolate 27 occurred at pH 5, temperature 90 oC and 50 oC, while xylanase isolate 18 achieve its optimum production time at the 18th and 36th hours of incubation culture. Xylanase isolate 18 achieved its optimum condition at pH 5 and temperature 90 oC and has half-life time 1 hour 7 minutes.
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Judul: Cycle Hamilton pada Graf Lengkap, Graf Regular, dan Graf 2-Connected 4-Regular Berorder Kurang dari Sepuluh
Abstrak: Suatu graf disebut graf Hamilton apabila graf tersebut memuat cycle Hamilton, yaitu cycle yang melewati setiap vertex tepat satu kali. Menentukan keberadaan cycle Hamilton pada suatu graf dapat menggunakan syarat cukup yang berupa teorema-teorema yang telah diperkenalkan sejak tahun 1950-an. Beberapa syarat cukup yang dibahas dalam karya ilmiah ini adalah syarat cukup yang berhubungan dengan graf lengkap dan graf regular. Suatu graf lengkap berorder 𝑛������ ≥ 3 dan graf r-regular berorder 𝑛������ ≤ 2𝑟������ + 1 merupakan graf Hamilton, Karena kedua graf tersebut memuat cycle Hamilton. Selanjutnya, syarat cukup tersebut digunakan untuk menentukan keberadaan cycle Hamilton pada graf 2-connected 4- regular berorder kurang dari 10.
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular