Judul: Adaptation of saccharomyces cerevisiae to cassava acid hydrolisates for bioethanol production.
Abstrak: Acid hydrolisates of cassava contain toxic substances i.e. 3,55 g/l HMF and 0,72 g/l furfural to ethanol producing yeast, Saccharomyces cerevisiae. This study is aiming at screening four strains of S. cerevisiae for their tolerance capacity to that acid hydrolisates. Out of four strains, S. cerevisiae IPBCC 05.548 showed the highest tolerance on the bases of ethanol production. It produced 4,1% (b/v) ethanol. Prior to adaptation, optimum sugar concentration and starter dosage were determined in sequence. Out of 15%, 18%, 20% and 24% concentration. S. cerevisiae IPBCC 05.548 showed the highest ethanol production (4,10% b/v) at 15% of total sugar. Among starter dosage (1, 2 and 3 times of 0,23% of sugar concentration), that were tested on optimal sugar concentration indicated that the twice of dosage was the best for ethanol production. Adaptation was then performed for 72 hours for each cycle. Of the cycles, the 9th cycle (648 hours) showed the highest specific growth rate (0,14g.h-1) as well as ethnol yield (4,13% b/v). Comparison of the adapted strain to unadapted strain proved that the adapted strain produced 30,78% higher ethanol yield than those of unadapted strain.
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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: Biologi Troides helena helena dan Troides helena hephaestus (Papilionidae) di Penangkaran
Abstrak: Indonesia adalah negara kepulauan beriklim tropik dengan berbagai tipe habitat dan ekosistem. Kondisi alam Indonesia merupakan habitat yang cocok bagi berbagai fauna termasuk kupu-kupu. Diperkirakan sekitar 4 000 – 5 000 jenis kupu-kupu terdapat di Indonesia. Troides helena merupakan salah satu kupu-kupu yang memiliki kombinasi warna sayap indah dan berukuran besar, sehingga menarik perhatian kolektor kupu-kupu. T. helena termasuk satwa yang diperdagangkan dan telah memasukkan devisa dari subsektor kehutanan Indonesia. Untuk mencegah dari kepunahan karena eksploitasi yang berlebihan, maka pemerintah melindungi T. helena melalui PP No. 7 Tahun 1999. Semua genus Troides masuk dalam daftar Appendix II CITES, sehingga perdagangan jenis ini harus merupakan hasil budi daya di penangkaran.
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