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: Potensi Khamir dalam Fermentasi Hidrolisat Rumput Laut (Kappaphycus alvarezii) Menjadi Bioetanol
Abstrak: Seaweed (K. alvarezii) contains galactose that can be used as raw material for bioetanol production. Some yeasts were able to use galactose for carbon source and energy source as well as converts it into bioethanol. This study was aimed to screening Pachysolen tannophilus IPBCC y 11.1149, Pichia anomala IPBCC y 11.1182, and IPBCC y 11.1192, and Saccharomyces cerevisiae IPBCC y 03.545 in their ability to produce bioetanol from seaweed hydrolysate. Prior to screening, these yeasts were determined their ability to ferment glucose and galactose to bioetanol. All strain were able to convert glucose to bioetanol, but only two strains can use galactose. These were P. tannophilus and S. cerevisiae. These isolates were tested for their ability to produce bioetanol from seaweed hydrolysate. P. tannophilus was the potential one. P. tannophilus produce more ethanol volume (0.50%-1.18%) comparing to S. cerevisiae (0.05%-0.11%). The ethanol concentration from both strain were different, P. tannophilus showed ethanol concentration higher (0.50%-1.18%) than S. cerevisiae (0.05%-0.19%). P. tannophilus had the substrate efficiency 16.45%-24.38% and fermentation efficiency 12.16%-23.13% it was higher than S. cerevisiae which has 20.76%-22.6% and 1.18%-2.19% respectively
Keyword: 

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