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: Truncated Stop Loss as a Optimal Solution of Reinsurance Agreement in One-Period Model
Abstrak: Reinsurance is one of risk management efforts of an insurance company, which is called the cedent. Similar with insurance, reinsurance constitutes the cedent to pay the premium. We consider one-period reinsurance model and derive a rule which minimizes the ruin probability of the cedent for a fixed reinsurance premium. Therefore, it is needed to construct an optimal reinsurance agreement for the cedent. The premium is calculated according to four different principles, i.e. economic, generalized zero-utility, Esscher, and mean-variance principles. Stop loss is a reinsurance contract which protect the insurance company for losses that exceed a certain amount. The result of this research shows that a truncated stop loss is an optimal agreement in the class of all reinsurance contracts with various premiums calculated using above mentioned principles.
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