Judul: Produksi Bioetanol dari Rumput Laut Kappaphycus alvarezii Menggunakan Khamir Saccharomyces cerevisiae IPBCC ALXVII
Abstrak: Kappaphyus alvarezii contains carrageenan type polysaccharide which consists galactose as its monomers. After acidly hydrolysis process, galactose can be converted into ethanol through fermentation process. However, some yeasts prefer glucose as their food substrate. One of the yeast from Surfactant and Bioenergy Research Centre (SBRC) Laboratory is Saccharomyces cerevisiae IPBCC ALXVII is expected can convert galactose inside hydrolyzed seaweed into ethanol. This study aims to analyze the potential of S. cerevisiae IPBCC ALXVII in production of ethanol from K. alvarezii seaweed. In this study, the inoculum of S. cerevisiae IPBCC ALXVII was prepared by repeated batch for eight times. Fermentation process used two hydrolyzed seaweed with different concentrate of sugar reductor. Fermentation with 150.46 g/L sugar reductor concentrate produced lower content of ethanol i.e. 1.69 g/L while with 57.33 g/L produced the highest content of ethanol i.e. 14.56 g/L with fermentation efficiency about 49.80%. The optimum fermentation time using S. cerevisiae IPBCC ALXVII was 144 hours.
Keyword: Bogor Agricultural University (IPB), energy, ethanol, hydrolysis, Kappaphycus alvarezii

Judul: Evaluasi Saccharomyces cerevisiae Teradaptasi Hidrolisat Kappaphycus alvarezii dalam Kemampuan Mengonversi Hidrolisat Menjadi Bioetanol
Abstrak: Bioetanol is one of renewable energy source that can be obtained by fermentation and is environmental friendly. The production of bioetanol needs two important components that are the substrate and fermentation agent. Kappaphycus alvarezii is a potential subrate to be fermented by Saccharomyces cerevisiae, the most common microorganism for fermentation process. This study aimed at determining the ability of the 9th generation slow adapted S. cerevisiae strain (IPBCC 05.548 AL IX) to convert K. alvarezii hydrolysates into bioetanol. The yeast growth in hydrolysates and Yeast Malt Glucose Pepton (YMGP) was maximum at 42 hour incubation. In the hydrolysates, the cell size was relatively longer and the number of cells with large size were more than those in the YMGP. About 90 mL hydrolysates K. alvarezii that was fermentated with 10 mL of 106 mL-1 inoculum yielded maximum bioetanol 1,94% (v/v) at 168 hours incubation. Its fermentation, and substrate efficiency were 36,57%, and 59,85%, respectively. At the same incubation time and 106 cells mL-1 inoculum, 1,02% (v/v) bioetanol was yielded with fermentation, and substrate efficiency were 21,29%, and 70,07% respectively
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Judul: Penggunaan Teorema Homeomorphy 2-Manifold dan Teorema Euler Poincare pada Torus 𝑇�� dan Simplicial Complex 𝐾��
Abstrak: Two dimensional topological spaces are said to be homeomorphic if they have the same topological invariant, where one of topological invariant used is an Euler characteristic. Homeomorphy 2-Manifold’s Theorem and Euler Poincare’s Theorem are used to distinguish two topological spaces. Homeomorphy 2-Manifold’s Theorem uses Euler characteristic to identify two dimensional topological spaces. Euler Poincare’s Theorem is an alternative way to find Euler characteristic with Betti number, which is topological invariant as well. The objective of this paper is to investigate the homeomorphism of torus 𝑇����� and simplicial complex 𝐾�����. Topological space torus and simplicial complex 𝐾����� have the same Euler characteristic, which is two. Based on Homeomorphy 2-Manifold’s Theorem topological space torus 𝑇����� and simplicial complex 𝐾����� is homeomorphic.
Keyword: simplicial, torus, Euler, homeomorphism, topology