Judul: Isolasi dan Identifikasi Bakteri Manolitik Laut dari Pulau Pari
Abstrak: Indonesia's tropical marine biodiversity of microorganisms have high potential and commercial value. This study focused on the isolation and identification of potential microbes which produce mannanase enzyme to hydrolyze mannan and eventually produce manno-oligosaccharides. Sampling was conducted in Pari island at Jakarta Bay area, the screening and observation of mannanase enzyme activity from those marine biodiversity have been conducted. The research succeed to collect 20 bacteria that could produce mannanase enzyme, three of them have the most high activity from qualitative analysis based on mannolytic index using congo red method for Pari 3, 4 dan 5 such as 4,33, 2,40, dan 2,60. Further quantitative analysis for these bacteria were conducted such as activity of mannanase using dinitrosalicylic acid method and resulted the highest activity is Pari 3 with 2,474 U/mL and Pari 4 with 1,193 U/mL both in the second day of fermentation, whereas Pari 5 with 1,087 U/mL in the third day of fermentation. Analysis 16S rRNA gene were showed that Pari 3, 4, and 5 are domain Bacteria, filum Firmicutes, class Bacilli, ordo Bacillaceae and genus Bacillus. For the spesific identification are using phylogenetic tree and concluded that Pari 3 has similar sequence 91.1% with Bacillus safensis and 92% Bacillus pumilus, from the both result showed the genetic relationship which is less than 97% in similarity therefore it was suggested that the bacteria Pari 3 is a new strain and can be further investigated. Whereas The results of Pari 4 identification has similar sequence 94.1% with Bacillus anthacis and 92.2% with the Bacillus cereus in the genetic relationship. The results of Pari 5 identification has similar sequence 97.1% with Bacillus anthracis and 95.2% with the Bacillus cereus in the genetic relationship.
Keyword: 

Judul: Purifikasi Parsial dan Karakterisasi Enzim Mananase dari Bacillus pumilus
Abstrak: Bacillus pumilus isolate is one of bacterial collection from Biotechnology Culture Collection (BTCC) LIPI, isolated from Pari island waters was examined to determine the ability of bacteria to degrade mannan from Locust Bean Gum (LBG). Based on qualitative analysis, this isolate showed the abilities to degrade mannan while the quantitative analysis showed the highest mannanase activity was obtained on the third day of incubation time at 3,2 U/mL with 0,9 U/mg specific activity. Initial purification using ultrafiltration 5000 WMCO showed mannanase activity at 5,1 U/mL with 1,44 U/mg specific activity. Enzyme purification by gel filtration produced a peak in fraction no.31 with mannanase activity at 4,2 U/mL with 4,00 U/mg specific activity. Analysis of hydrolitic products by thin layer chromatography showed that the main products from Locust Bean Gum are manobiose, manotetraose and manohexaose. Maximum activity of the mannanase enzyme produced by B. pumilus isolate occurred at pH 5,0 and temperature of 40°C. This enzyme has 30,17 kDa single protein band when running with SDS PAGE with Michaelis Menten (Km) and maximum velocity (Vmax) at 0,076 mg/mL and 0,02 U/mg respectively.
Keyword: 

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.
Keyword: