Judul: Pengaruh Galaktosa, Glukosa dan Hidrolisat E. cottonii Terhadap Pertumbuhan P. tannophilus dan Produksi Bioetanol
Abstrak: P. tannophilus is one good producer of ethanol in the mixture pentose and hexose. The objectives of this research was to determine the effect of glucose, galactose, and hydrolyzate E. cottonii to P. tannophilus growth and production of bioethanol. This research focused on the analysis of the growth curve and the production of bioethanol. The growth curve is based on the concentration and type of substrate. Then do the fermentation. Based on the growth curve can be determined P. tannophilus incubation time is 24 hours. The result of P. tannophilus fermentation on YMP galactose and glucose medium with concentration of 2.5%, 5%, 7.5% and 10% were analyzed with analysis of variance and Duncan test, the concentration and type of sugar found to affect the production of ethanol by P. tannophilus. While ethanol production on hydrolyzate E. cottonii also affect the production of ethanol and growth P. tannophilus
Keyword: growth curve, bioethanol production, P. tannophilus

Judul: Fermentation modification of acid hydrolisates of euchema cottonii to produce bioethanol using Saccharomyces cerevisiae and Pachysolen tannophilus.
Abstrak: Euchema cottonii is a red algae that is formed from linear polysaccharide commonly called "carrageenan". Carrageenan is galactan (polysaccharide sulfate linear hydrophilic) which is a polymer consists of galactose. The research objective is to modify bioethanol fermentation by batch condition from seaweed (Euchema cottonii) acid hydrolisates to produce a high yield of bioethanol. The study was conducted in two stages. The first stage is a preliminary phase which consists of size reduction, drying, characterization of E. cottonii with parameters tested were carbohydrates (cellulose and hemicellulose), protein, crude fiber, ash, and water content. The last stage is the preliminary were hydrolysis of E. cottonii using sulfuric acid so that the cellulose and hemicellulose components of E. cottonii can be hydrolyzed into constituent sugars (galactose) and then filtered the results so obtained solids hydrolysis and hydrolyzate containing galactose. The second stage is the stage of primary research which is divided into two stages, adaptation stages and fermentation stages. In the adaptation phase, yeast was adapted in media containing galactose to condition the yeast in media containing galactose. The second stage is the fermentation of acid hydrolisates of E. cottonii to produce bioethanol using two kinds of yeast that has been adapted (Saccharomyces cerevisiae IPBCC AL IX and Pachysolen tannophilus IPBCC AC IX). For the fermentation process, the medium of acid hydrolisates of E. cottonii added vitamins, nitrogen, and minerals (trace elements) to spur the growth of activity in the yeast consumes galactose to produce bioethanol. Euchema cottonii has high polysaccharides content and those can be converted into fermentable sugar through acid or enzymatic hydrolysis. Polysaccarides of red algae Euchema cottonii consists of 29.45% (db) carbohydrates, 3.21% (db) hemicelluloses, and 11.30% (db) celluloses. Type of sugar was obtained in acid hydrolisates of Euchema cottonii consists of 4.95% galactose, 0.25% glucose, 0.04% xylose, and 0.02% maltoheptaosa. The highest ethanol production from adapted Saccharomyces cerevisiae IPBCC AL IX was 2.38% (v/v ethanol in fermentation broth), with 79.09% substrate efficiency and 56.30% fermentation efficiency for 6 days incubation. The highest ethanol production from adapted Pachysolen tannophilus IPBCC AC IX was 0.11% (v/v ethanol in fermentation broth), with 15.39% substrate efficiency and 2.60% fermentation efficiency for 4 days incubation. The highest ethanol production with refreshed culture treatment using adapted Pachysolen tannophilus IPBCC AC IX after fermentation lasts 24 hours by adapted Saccharomyces cerevisiae IPBCC AL IX was 0.81% (v/v ethanol in fermentation broth), with 82.42% substrate efficiency and 19.79% fermentation efficiency for 6 days incubation. The highest ethanol production with refreshed culture treatment using adapted Saccharomyces cerevisiae IPBCC AL IX after fermentation lasts 24 hours by adapted Saccharomyces cerevisiae IPBCC AL IX was 1.76% (v/v ethanol in v fermentation broth), with 53.06% substrate efficiency and 43.53% fermentation efficiency which fermented for 6 days. The highest ethanol production with different of reducing sugar concentration treatment on media of fermentation after 6 days incubation was 2.13% (v/v ethanol in fermentation broth), with 76.31% substrate efficiency and 50.97% fermentation efficiency with reducing sugar consentration on media in the start of fermentation was 6.57% (w/v).
Keyword: bioethanol, yeast adaptation, Euchema cottonii, Pachysolen tannophilus, Saccharomyces cerevisiae, refreshed culture treatment, reducing sugar consentration treatment

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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