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
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Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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