Judul: Karakterisasi enzim hidrolase bakteri dari mata air soda Parbubu, Tapanuli Utara
Abstrak: North Tapanuli has a soda fountain as a source of potential biotic diversity of Indonesia, one of which is the hydrolytic bacteria. The purpose of this study was to isolate bacteria from the soda fountain and test Parbubu hidrolasenya enzyme activities, ie lipase, protease, and cellulase enzyme hidrolase and characterize the best in certain conditions of temperature and pH. Isolation of bacteria from the soda fountain Parbubu using pour plate method produced 23 isolates of bacteria. Test semikualitatif hidrolase enzyme using hydrolytic enzymes in media index showed that the bacterial isolates P9 has the highest lipase activity. Harvest time P9 bacterial lipase based on the growth curve and enzyme production curves, ie on the seventh hour of incubation. Lipase activity determined with titrimetric method shows that the fraction of the enzyme by precipitation (60-80)% of ammonium sulfate has the highest activity, that is equal to 3.5245 U / mL or 5992 times the activity of crude extract. Lipase enzyme has optimum activity at pH 7, at 5.9593 U / mL and at a temperature of 90 º C with the activity of 4.9019 U / mL.
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Judul: Karakterisasi Morfologi Sel dan Penapisan Aktivitas Hidrolisis dari Isolat Bakteri Tanah Pulau Muna, Sulawesi Tenggara
Abstrak: Bakteri penghasil enzim ekstraselular, khususnya enzim amilase, selulase, dan protease, dapat digunakan dalam berbagai industri. Lima belas isolat bakteri tanah yang diisolasi dari Pulau Muna, Sulawesi Tenggara, belum diketahui potensinya sebagai penghasil enzim-enzim tersebut. Penelitian ini bertujuan mengkarakterisasi morfologi sel dan menapis aktivitas amilolitik, proteolitik dan selulolitik dari bakteri tanah yang diisolasi dari Pulau Muna. Karakterisasi morfologi dilakukan dengan pewarnaan Gram. Penapisan bakteri dilakukan dengan metode kualitatif pada medium padat. Berdasarkan pengecatan Gram, 5 Isolat tergolong ke dalam bakteri Gram negatif dan 10 Isolat tergolong bakteri Gram positif, dengan bentuk sel yang bervariasi yaitu batang panjang dan bulat. Empat dari 15 isolat memiliki karakter hemolisis negatif atau gamma hemolisis sehingga diduga tidak bersifat patogen. Empat isolat tersebut selanjutnya digunakan untuk penapisan aktivitas hidrolisis terhadap amilum, selulosa, dan protein. Isolat M7 dan P7 mampu menghasilkan protease, selulase, dan amilase, sedangkan 2 isolat lainnya yaitu M4 dan P5 hanya mampu menghasilkan protease. Keempat bakteri tersebut dapat diteliti dan dikembangkan lebih lanjut sebagai penghasil enzim amilase, protease dan selulase., Bacteria producing extracellular enzymes, especially amylase, cellulase and protease enzymes, can be used in various industries. Fifteen isolates of soil bacteria isolated from Muna Island, Southeast Sulawesi, have no known potential as producers of these enzymes. This research aims to characterize cell morphology and screen the amylolytic, proteolytic and cellulolytic activities of soil bacteria isolated from Muna Island. Morphological characterization was carried out using Gram staining. Bacterial screening was carried out using qualitative methods on solid medium. Based on Gram staining, 5 isolates were classified as Gram negative bacteria and 10 isolates were classified as Gram positive bacteria, with varying cell shapes, namely long rods and round. Four of the 15 isolates had negative hemolysis or gamma hemolysis characteristics so they were suspected not to be pathogenic. The four isolates were then used to screen for hydrolysis activity on starch, cellulose and protein. Isolates M7 and P7 were able to produce protease, cellulase and amylase, while the other 2 isolates, namely M4 and P5, were only able to produce protease. These four bacteria can be researched and developed further as producers of amylase, protease and cellulase enzymes
Keyword: Amilase, hemolisis, indeks hidrolitik, Protease, Selulase

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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