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.
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Judul: Rekayasa Bioproses Produksi Bioetanol dari Hidrolisat Pati Sagu (Metroxylon sp.) Menggunakan Saccharomyces Cerevisiae Var.ellipsoides Pada Kultivasi Nir-Sinambung dan Semi Sinambung:
Abstrak: Starch of sago is one of the sources of ethanol which is able to be produced by enzymatic hydrolysis and followed by cultivation process. It has high concentration of carbohydrate (80 %), so it can produce glucose highly with enzymatic hydrolysis process. The total amount of glucose has correlation with amount of ethanol, in cultivation process. The first step of research was to prepare substrate from sago starch which was hydrolysed enzymatically using α- amylase and amyloglucosidase (AMG) enzymes. Preliminary research was conducted to determine optimum concentration in which S.cerevisiae var.ellipsoides can live and produce the highest ethanol content. The concentrations being tested were 18, 24, 30 and 36 % (g/L) of total sugar. The main research consists of two systems: batch and fed-batch. Result shows that 24 % concentration (g/L) was find to be the optimum consentration for S.cerevisiae var.ellipsoides with ethanol production reaches up to 10,2 ± 0,000 % (w/v). One of the main research is using batch cultivation. The best result of highest ethanol concent was reached (10,77 ± 0,000 % w/v) when aeration was stopped after biomass condition has reached the maximum condition. The best result on fed-batch cultivation with the highest ethanol concentration (12,05 ± 0,00 % w/v) also was gained at the same treatment with feed concentration of glucose 16 % g/L. Based on calculation of cultivation kinetic parameters, it is shown that in batch cultivation the highest Yp/s, Yp/x (0,15; 0,47; 4,48) was gained on the third treatment that is aeration stopped at 30th hour. On fed-batch cultivation, the highest Yp/s and Yp/x value (0,51 and 5,05) is shown on treatment of which aeration is stopped after 30th hour and feed concentration of 16 % g/L.
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Judul: Metric Solution and Electromagnetic Field Tensor of Black Hole in 4+1 Dimensional Kerr-Newman Space-Time
Abstrak: Solusi metrik Kerr-Newman merupakan solusi paling umum untuk black hole. Konstruksi metrik pada dimensi 4+1 didasarkan pada asumsi bahwa hukum-hukum fisika berlaku di semua dimensi. Tujuan penelitian ini adalah untuk mengonstruksi solusi metrik Kerr-Newman 4+1 dimensi beserta tensor medan elektromagnetiknya. Dilakukan pengambilan tebakan, reverse engineering, analisis persamaan medan Einstein, manipulasi aljabar, dan pengambilan limitasi untuk mengonstruksi dan membuktikan solusi metrik dan tensor medan elektromagnetik. Terdapat komponen-komponen off-diagonal pada tensor metrik yang diperoleh. Hal ini berkaitan dengan keberadaan parameter momentum angular a. Keberadaan parameter muatan Q dan parameter momentum angular a pada black hole Kerr-Newman mengindikasikan keberadaan parameter magnetik yang muncul pada black hole Kerr-Newman. Keberadaan parameter magnetik berkontribusi dalam membentuk medan potensial yang diajukan, dimana medan potensial tersebut terbukti benar dengan menganalisis komponen-komponen tensor medan elektromagnetik yang diperoleh., Kerr-Newman metric solution is the most common solution of black hole. Metric construction on 4+1 dimensions based on the assumption that physics law valid in all dimension. The aims of this research is to construct Kerr-Newman metric solution in 4+1 dimension and it’s electromagnetic field tensor. Guesswork, reverse engineering, analysis of Einstein’s field equation, algebraic manipulation, and limitation taking are carried out to construct and prove metric solution and electromagnetic field tensor. There is off-diagonal components in metric tensor obtained. It is related to the existence of angular momentum parameter a. The existence of charge parameter Q and angular momentum parameter a in Kerr-Newman black hole indicates the existence of magnetic parameter which appear in Kerr-Newman black hole. Magnetic parameter existence is contribute in the forming of potential field which submitted, whereby this potential field is proven correct by analyzing electromagnetic field tensor components obtained.
Keyword: Einstein field equation, Electromagnetic field tensor, Kerr-Newman metric solution, Magnetic parameter