Judul: Optimasi Enzim Cocktail dalam Sakarifikasi dan Fermentasi Simultan untuk Produksi Bioetanol dari Tandan Kosong Kelapa Sawit
Abstrak: Tandan kosong kelapa sawit (TKKS) berpotensi dijadikan bahan baku produksi bioetanol. Produksi bioetanol terdiri atas beberapa tahap, salah satu tahap termahal adalah hidrolisis. Penggunaan enzim xilanase, feruloil esterase (FAE) dan enzim komersial Cellic® Ctec2 dapat digunakan untuk mengefisienkan proses hidrolisis. Penelitian ini bertujuan memanfaatkan TKKS sebagai bahan baku produksi bioetanol dan mengoptimasi konsentrasi enzim cocktail untuk sakarifikasi yang terdiri atas enzim xilanase, FAE, dan Cellic® CTec2, dan fermentasi bioetanol menggunakan Saccharomyces cerevisiae dengan metode sakarifikasi dan fermentasi simultan (SFS). Tahapan penelitian meliputi praperlakuan bagas tebu sebagai bahan baku produksi enzim, produksi enzim xilanase dan FAE, dan reaksi SFS. Hasil penelitian menunjukkan bahwa belum didapatkan konsentrasi optimum enzim cocktail karena konsentrasi etanol pada perlakuan penambahan enzim tidak berbeda nyata dengan kontrol., Palm oil empty fruit bunch (EFB) is potential as raw material for bioethanol production. Bioethanol production consists of several stages; the most expensive one is hydrolysis. The use of xylanase, feruloyl esterase (FAE) enzymes, and the commercial Cellic® Ctec2 can be used to streamline the hydrolysis. This study aims to utilize EFB as a raw material for bioethanol production and optimize the cocktail enzyme concentrations for saccharification consisting of a xylanase, FAE, and Cellic® CTec2 enzymes, and bioethanol fermentation using Saccharomyces cerevisiae through the saccharification and simultaneous fermentation (SSF) method. The research stages include the implementation of sugarcane bagasse as a raw material for enzyme production, the production of enzymes xylanase and FAE, and the SSF reaction. The results showed that the optimum concentration of cocktail enzymes had not been obtained because the ethanol concentration in the enzyme addition treatment was not significantly different from the control.
Keyword: bioetanol, enzim cocktail, hidrolisis, TKKS, SFS, bioethanol, cocktail enzymes, EFB, hydrolysis, SSF

Judul: Optimasi Proses Hidrolisis Kimiawi dan Enzimatis Tandan Kosong Kelapa Sawit Menjadi Glukosa untuk Produksi Etanol
Abstrak: Recently, energy especially from petroleum fuel become a serious problem for the whole countries in the world, including Indonesia. Decreasing world’s petroleum stock make its price is very high. So, it is urgent to search other alternative energy sources, such as bioethanol. Oil Palm Empty Bunches (OPEB) are found abundantly as waste of CPO production. It is rich in lignocellulose content. After delignification by white rot fungi Omphalina sp, cellulose from OPEB can be degraded to glucose as the raw material for etanol production by hydrolysis process. In this research, hydrolysis were done chemically using H2SO4 and HCl and enzymatically using cellulolytic bacteria and Trichoderma isolates. Chemical hydrolysis was carried out in autoclave at temperature of 121oC and varation in acid concentration (0.1N; 0.5N; 1N; and 2N) and hydrolysis time (20; 40; 60; 120; and 240 min). The condition was then reoptimalized by increasing the temperature to 200 0C and variation hydrolisis time (5;7,5;10;12,5; dan 15 min). Enzymatic hydrolysis were done by two methods, namely simultaneuos and separated bacth methods using Trichoderma or cellulolytic bacteria and Saccharomyces cereviceae. Delignification process increased cellulose content from 47.18% to 49.09%. The optimum condition by chemical hydrolisis with H2SO4 2N was resulted in sugar content (30,86%) with ethanol production 1.82%. By enzymatic methods, higher sugar content was obtained by Trichoderma isolate with incubation time 72 hours. The sugar content was 1.46 g/L and ethanol production was 0.33%. Ethanol production from simultaneuos process by cellulolytic bacteria was the same as ethanol production from Trichoderma by separated batch process i.e as much as 0.27 %
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Judul: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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