Judul: Optimization of Oil Palm Empty Fruit Bunch Pretreatment with Microwave Heating and Aluminium Salt Catalysts for Reducing Sugar Production
Abstrak: Biomassa TKKS berpotensi sebagai bahan baku produksi bioetanol, tetapi tantangan yang masih dihadapi dalam produksi bioetanol dari bahan lignoselulosa adalah praperlakuan yang efisien dan ramah lingkungan. Penelitian ini bertujuan untuk mengetahui kondisi optimum praperlakuan TKKS dengan menggunakan microwave dan katalis garam aluminium, yaitu AlK(SO4)2 dan Al2(SO4)3, untuk produksi gula pereduksi yang dapat difermentasi lebih lanjut menjadi bioetanol. Optimasi dilakukan melalui metode one factor at a time (OFAT). Pada langkah 1, analisis optimasi suhu (180, 190, dan 200 °C), dengan waktu 6 menit dan jumlah katalis 200 µmol/g biomassa. Pada langkah 2, analisis optimasi waktu pemanasan (2, 4, 6, 8, dan 10 menit) dengan suhu optimum (berdasarkan hasil pada langkah 1) dan jumlah katalis tetap (200 µmol/g biomassa). Pada langkah 3, analisis optimasi jumlah katalis (0, 100, 200, 300, dan 400 µmol/g biomassa) dengan suhu optimum (berdasarkan hasil langkah 1) dan waktu pemanasan optimum (berdasarkan hasil langkah 2). Total hasil gula pereduksi yang diperoleh digunakan sebagai parameter dalam analisis optimasi. Karakteristik TKKS yang diberi perlakuan awal meliputi komponen kimia, gugus fungsi, indeks kristalinitas, dan sifat morfologi pada kondisi optimum dan dibandingkan dengan TKKS tanpa perlakuan. Hasil penelitian menunjukkan bahwa kondisi optimum praperlakuan TKKS dengan pemanasan gelombang mikro dengan katalis AlK(SO4)2 adalah pada suhu 200 °C, selama 6 menit, dengan katalis 300 µmol per g biomassa. Kondisi optimum dengan katalis Al2(SO4)3 adalah pada suhu 180 °C, selama 6 menit, dengan katalis 200 µmol per g biomassa. Pada kondisi tersebut rendemen gula pereduksi masing-masing mencapai 61,7 dan 58,1% berdasarkan biomassa TKKS awal., The OPEFB has the potential as a raw material for bioethanol production, but the challenge that is still faced in the production of bioethanol from lignocellulosic material is an efficient and environmentally friendly pretreatment. This study aims to determine the optimum conditions of OPEFB pretreatment by using microwave and aluminum salt catalysts, i.e. AlK(SO4)2 and Al2(SO4)3, for the production of reducing sugars that could be further fermented to bioethanol. The optimization was conducted through the one factor at a time (OFAT) method. In step 1, the factor optimized was the temperature (180, 190, and 200 °C), at a fixed time (6 min) and a fixed amount of catalyst (200 µmol/g biomass). In step 2, the optimized factor was a heating time (2, 4, 6, 8, and 10 min.) at fixed temperature (based on the result in step 1) and fixed amount of catalyst (200 µmol/g biomass). In step 3, the factor optimized was the amount of catalyst (0, 100, 200, 300, and 400 µmol/g biomass) at a fixed temperature (based on the result of step 1) and a fixed heating time (based on the result of step 2). The total reducing sugar yield obtained used as a parameter in the optimization. The characteristics of pretreated OPEFB, including chemical composition, functional group, crystallinity index, and morphological property at optimum conditions were also compared with those of untreated OPEFB. The results showed that the optimum conditions of OPEFB pretreatment by microwave heating with AlK(SO4)2 catalyst were at 200 °C, for 6 min, with 300 µmol catalyst per g biomass. Optimum conditions with Al2(SO4)3 catalyst were
Keyword: aluminium salts, catalyst, microwave, OPEFB, pretreatment, reducing sugar yield

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 %
Keyword: 

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.
Keyword: