Judul: Application of Microwave Heating in Cocoa Pod Husk (CPH) Biomass Hydrolysis for Bioethanol Production
Abstrak: Cocoa Pod Husk (CH) is one of the most abundant biomass in Indonesia, but its use is still limited to making fertilizer and animal feed. The abundant amount of CPH and its contents are considered suitable to be used as raw material in the second generation ofethanol production. The high concentration of lignin in CPH can inhibit the rate of hydrolysis, so it is necessary to pre-treat CPH samples. It is also necessary to pay attention to the method used in the process of hydrolyzing CPH samples prior to fermentation so that they can produce high ethanol during the fermentation process. Fermentation stress can affect the growth and productivity of yeast isolates, so it is necessary to characterize the isolates in terms of their resistance to various fermentation stresses. This research began with the process of preparing CPH samples and continued with the process of hydrolyzing the samples using microwave heating. Rejuvenation of yeast isolates was carried out by growing isolates on YPD medium. Yeast isolates were then selected based on their ability to ferment xylose using oxidative fermentative media. Isolate characterization was carried out on selected yeast isolates including resistance to temperature stress (30 °C, 37 °C, and 40 °C), pH stress (3, 4, and 5), and ethanol stress (6%, 8%, 10%, 12%, and 14%) using the spot assay method. Growth curves were prepared by measuring the optical density (OD) value of the yeast isolates Y001 and Y003 at a wavelength of 600 nm per 6 hours for 72 hours. The final stage of this study was to measure the ethanol produced during the fermentation process using HPLCevery 24 hours for 96 hours. Analysis of the chemical components of the two P H samples before and after treatment using hydrogen peroxide showed a decrease in lignin levels of34% of the total lignin samples. Hydrolysis of ICS 60 variety CPH samples using the microwave-assisted hydrolysis method produced hydrolysate with a high concentration of glucose-xylose with a heating time of 12 minutes. Selection of ethanol fermenting yeast using oxidative fermentative media showed that isolates Y001 and Y003 were able to ferment xylose and were resistant to various fermentation stresses including being able to grow up to 40 °C, resistant to ethanol stress up to 14% and able to grow at pH .3 The highest ethanol was produced at the E3 (liquid hydrolysate + 1% yeast extract + 2% peptone + 2% glucose + 2% xylose) treatment was 11.3 g/L with ethanol yield of 0.31 g/g., Cocoa Pod Husk (CPH) merupakan salah satu biomassa yang melimpahdi Indonesia, akan tetapi pemanfaatannya mash terbatas pada pembuatan pupuk dan pakan ternak. Melimpahnya jumlah CPH dan kandungan yang dimilikinyadinilai c o o k untuk dijadikan bahan baku dalam produksi etanol generasi kedua. Konsentrasi lignin yang tinggi pada CPH dapat menghambat laju hidrolisis sehingga perlu dilakukannya pra-perlakuan sampel CPH. Metode yang digunakan dalam proses hidrolisis sampel P H sebelum difermentasi juga perlu diperhatikan sehingga dapat menghasilkan etanol yang tinggi s a t proses fermentasi. Cekaman fermentasi dapat mempengaruhi pertumbuhan dan produktivitas isolat khamir sehingga perlu dilakukan karakterisasi isolat berupa
Keyword: Pretreatment, hydrolysis, microwave-heating, fermentation-related stresses, ethanol

Judul: Kajian Pemanfaatan Pod Kakao (Theobroma cacao) melalui Hidrolisis Asam Lignoselulosa untuk Menghasilkan Etanol.
Abstrak: Cocoa is one of commodities that its role is important enough for the national economy. Cocoa commodity exports ranked third in the agriculture sector contributes foreign exchange, after the rubber and palm oil. Currently Indonesian cocoa production ranks third largest after the Ivory Coast and Ghana. In 2006 cocoa exports reached U.S. $ 975 million, an increase of 24.2% over the previous year (Suryani and Zulfebriansyah, 2005). Increased efforts in the field led to increased cultivation of cocoa pod waste. This is a challenge, given the amount of cocoa pod components for 73.73% of the cacao fruit (Siswoputranto, 1983). If the cocoa pod is not handled properly it will result in losses. In the research is studied on the acid hydrolysis using cocoa pod to produce ethanol. In addition to get the best treatment of acid hydrolysis that is affected by acid concentration and hydrolysis time and to get the highest yield of sugar and ethanol. This research was conducted in three main stages that were preliminary treatment of raw material preparation and characterization of raw materials, acid hydrolysis, and fermentation to produce ethanol. Hydrolysis of cocoa pod is done in two stages using sulfuric acid. In the first hydrolysis used sulfuric acid concentration of 1% with a time of hydrolysis for 1, 2, 3, 4, 5, 6, and 7 hours. In the second hydrolysis using acid with higher concentrations of 5, 10, 15, and 20% with hydrolysis time of 1, 2, 3, 4, and 5 hours. Analysis was conducted on the reducing sugar, total sugar, dextrose equivalent, and fiber components of lignocellulose. Fermentation using two different substrates derived from the hydrolysis of the first stage and second stage. In fermentation measured volume of CO2 formed, ethanol content, total residual sugar, the efficiency of substrate utilization and product yield of ethanol. On the characterization of raw materials obtained value of cocoa pod ash content 1.87% (db), fat 3% (db), protein 2.25% (db), carbohydrate 92.89% (db), and 53.82% crude fiber (db). Crude fiber fraction containing cellulose 28.78% (db), hemicellulose 8.70% (db) and lignin 42.90% (db). In the first hydrolysis, the results of analysis showed that the highest reducing sugar of 27.31 mg/ml was produced from treatment of 1% sulfuric acid and hydrolysis time of 4 hours. The highest total sugar also produced from the same treatment with a value of 32.74 mg/ml. Dextrose equivalent values ranged from 50.63% to 84.32%. On analysis of lignocellulose after the first hydrolysis, there is a decrease of lignin content, hemicellulose, and cellulose so that its value in a row to 30.82%, 6.52% and 25.75%. In the second hydrolysis, the best treatment that produces the highest reducing sugar and total sugar by using 5% acid concentration and time of hydrolysis for 4 hours. This treatment produces reducing sugar 15.91 mg/ml and the total sugar 29.26 mg/ml. In the second hydrolysis dextrose equivalent values ranged from 47.08% to 89.67%. Lignocellulose fiber components of cocoa pod is decreasing because the second hydrolysis, so that the lignin content to 28.88%, 4.45% hemicellulose, and cellulose 21.98%.
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Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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