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: Penambahan Glukosa sebagai Kosubstrat dan Pengaruhnya terhadap Produksi Xilitol oleh Candida guilliermondii
Abstrak: Xylitol is a five-carbon sugar alcohol and used commercially in various fields. Xylitol can be produced by solid-liquid extraction from fruits and vegetables, also chemical synthesis which is expensive and energy-intensive. Therefore, an alternative inexpensive production techniques is required, one of them is using microorganism. The purposes of this research were to determine the optimum incubation time for the growth of C. guilliermondii, and xylitol production, also to determine the best ratio variation of glucose:xylose. Fermentation was carried out at 300C with shaking speed 120 rpm. Ratio variation used in this research were (glucose:xylose) 1:25, 1:12, 1:5, 1:2.5. Xylitol concentration was measured with spectrophotometer based on D-sorbitol/Dxylose Kit. The results showed the log phase of the growth of C. guilliermondii at 12-36 hour, and the optimum incubation time to obtain the highest amount of xylitol at 72 hour. The best variation ratio of glucose:xylose is 1:5 with initial glucose concentration 9 g/L and xylose concentration 45 g/L. Xylitol obtained from ratio 1:5 was 2.85 g/L while xylitol obtained from control medium, which is the medium that contained only xylose 45 g/L was 0.57 g/L, thus the addition of glucose to fermentation medium can increase the production of xylitol.
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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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