Judul: Aktivitas Keratinase Bacillus licheniformis dalam Memecah Keratin Bulu Ayam
Abstrak: Tepung bulu ayam sangat potensial dikembangkan menjadi bahan baku pakan sebagai sumber protein, karena kandungan proteinnya tinggi. Namun kendala yang dihadapi adalah kandungan senyawa kreatin yang cukup tinggi. Kreatin merupakan peotein serat, tidak larut dalam air dan sulit dicerna. Rantai peptida dalam keratin terbentuk dalam bentuk pilin atau beliks dan saling berhubungan dengan ikatan disulfida dan ikatan hidrogen. Hal inilah yang menyebabkan kreatin sulit dicerna.
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Judul: Pemurnian dan Karakterisasi Enzim Keratinase dari Bacillus sp. BE-1
Abstrak: The keratinase studied in this research is an extracellular protease produced by Bacillus sp. BE-1. Feather meal substrates were prepared from native chicken feather, treated by sodium hydroxide at temperature of 1000C for 15 minutes to render crude keratinase extract. The crude keratinase was then purified by 2 steps of coloumn chromatography which are Hydrophobic Interaction Chromatography (HIC) and Gel Filtration Chromatography (GFC). Butyl Sepharose (HIC) increased keratinase activity to 67-fold. Further purification using Sephacryl S200-HR (GFC) increased keratinase activity up to the range of 116-515 fold. The highest specific activity of the keratinase was 35,9 U/mg with feather meal as substrate. This keratinase can be completely inhibited by ethylene diamine tetra acetic acid (EDTA). Additon of Mn2+ increased this keratinase activity significantly (about 51-fold) while Mg2+ increased the activity slightly (about 3-fold). Zymogram analysis resulted in that the purified keratinase consisted of two proteases with molecular weight 82 kDa and >97 kDa.
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Judul: Variabilitas Arus di Sekitar Selat Sunda Tahun 2007-2010 dari Hasil Model INDESO
Abstrak: Model output of high-resolution (1/12°) ocean general circulation model from INDESO project between 2007-2012 were used to investigate the structure and variability of currents at two locations around the Sunda Srait, one location is in Java Sea (JS) and the other is in Indian Ocean (IO) side. Model sea surface height (SSH) is validated with altimetry data, which shows a high correlation coefficient of 0.90 in the IO and 0.76 in JS. In general, both model and altimetry data indicate that SSH in JS is always higher that found in IO. However, between November-January each year, there exists a reversal flow northward in Sunda Strait, which may be related to arrival of coastally trapped Kelvin waves. An intensification of current appears near surface layer both in JS and IO. Analysis of power spectral density energy exhibits a wide range of current variability from intra-seasonal, semi-annual and annual time-scales. Power density energy of zonal current component is much stronger that that meridional component, and amplitude of energy is much stronger in IO it show that current in IO is stronger than JS. Cross correlation analysis show that there is strong relation between between JS and IO currents fluctuation which showed by coherence value between two areas of 0,99.
Keyword: Sunda Strait., Power spectral density analysis, Ocean general circulation model 1/12, Current vertical structure, Current Variability