Judul: Biokonversi Lignoselulosa Limbah Sabut Kelapa Menjadi Bioetanol Menggunakan Trichoderma reesei, Zimomonas mobilis dan Pichia stipitis
Abstrak: Bioethanol is an alternative fuel used to reduce dependence on fossil fuels. Bioethanol can be made from raw materials containing lignocellulose. Coconut coir waste has a high content of lignocellulose so it is potential as bioethanol source. The purpose of this research is to showed the effect of concentration variations of substrate from coconut coir waste to the bioethanol production through simultaneous saccharification and fermentation (SFS) using Trichoderma reesei, Pichia stipitis and Zymomonas mobilis. In this research, pretreatment process there are delignification, hydrothermal I and hydrothermal II. Concentration variations are 0.3%, 0.4%, and 0.5% (w/v). Ethanol concentration was measured by gas chromatography method. The results showed the highest productivity was obtained at a substrate concentration of 0.3% at a concentration of bioethanol produced by 10:47 g / L with the long process of SFS 4 days..
Keyword: Bogor Agricultural University (IPB), Coconut coir, SFS, Waste, Bioethanol

Judul: Produksi Bioetanol dari Limbah Tanaman Jagung Melalui Sakarifikasi dan Fermentasi Simultan dengan Kultur Campuran Saccharomyces cereviseae dan Pichia stipitis
Abstrak: Corn crop waste as a lignocellulosic material has a large potential in Indonesia. Lignocellulosic material is a renewable raw material for ethanol production. Most of the composition of lignocellulisic materials consist of cellulose, hemicellulose, and lignin. Cellulose hydrolysis will produce glucose that can be fermented into ethanol by Saccharomyces cereviseae. Hemicellulose hydrolysis will produce xylose. Sacharomyces cerevisiae is the most applied and traditional microorganism for ethanol production. It has a high ethanol tolerance, and high yields and rates of fermentation, but its inability to ferment xylose, the second most abundant sugar in nature, limits its use in biofuel production. This study applies simultaneous saccharification and fermentation techniques to the production of ethanol from corn crop waste materials using a culture volume Saccharomyces ceseviseae, Pichia stipitis, and mixed culture of Saccharomyces cereviseae and Pichia stipitis.Simultaneous saccharification and fermentation with individual yeasts Pichia stipitis shows the best results with high ethanol at 5.84 g/l and yield 0.11. Saccharomyces cereviseae and Pichia stipitis mixtures with etnanol 4.34 g/l and yield 0.10, and Saccharomyces cereviseae at least with the results 3.79 g/l ethanolo and yield 0.07 at the time of 96 hours. The results of this study indicate that at 96 hours of mixed culture of Saccharomyces cereviseae and Pichia stipitis not improve the performance their single culture. Further research still needs to be done by optimizing the ratio and between the two yeasts and sequence inoculation.
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: