Judul: Produksi Biohidrogen Menggunakan Sorgum Manis (Sorghum bicolor (L.) Moench) oleh Enterobacter aerogenes ADH-43 pada Reaktor Packed-Bed
Abstrak: Biohydrogen as gas produced from the activity of microorganisms is an environmentally friendly alternative energy because the production process does not require large energy and combustion results only in the form of water vapor and heat without producing waste that can pollute the environment. This research aims to produce H2 through fermentation with sweet sorghum (Sorghum bicolor (L.) Moench) as a main substrate using Enterobacter aerogenes ADH-43 in continuous mode at packed bed bioreactor. This research was conducted by the anaerobic fermenting E. aerogenes ADH-43 in medium containing about 4.27% total sugar in the anaerobic packed bed reactor that was operated in batch mode at first stage to find the value of specific growth rate of cells which was them used to determine the dilution rate (D). Dilution rates tested in this study were: D = 0.10, 0.15 and 0.20/ h. During fermentation the temperature was controlled at 37 ± 1oC. Cultivation were carried out until steady state in which the amount of H2 produced, pH, and OD (optical density) were constant. Fermentation at each D was carried out with three replications. Observations and analysis were done by measuring pH, OD, cell dry weight, total sugar, reducing sugar content, organic acid content and the amount of gas. In batch mode, H2 flow rate obtained was 8.26 L H2/L substrate and yield of 3.79 mol H2/ mol total sugar, whereas in continuous mode D = 0.15/ h was found to be optimum with a yield of 0.67 mol H2/ mol total sugar and H2 production of 10.56 ml H2/ min (1.41 L H2/ L h; 62.84 mmol / L h). As a comparison using molases as a main substrate, D=0,15/ h produced a smaller yield of 0.46 mol H2/ mol total sugar and H2 production was 7.79 ml H2/ min (1.04 L H2/ L h and 46.42 mmol H2/ L h).
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Judul: Perbandingan Kinerja Produksi Bioetanol Menggunakan Bagas Sorgum Manis (Sorghum bicholor L) Dengan Sakarifikasi Fermentasi Simultan dan Terpisah.
Abstrak: Peningkatan kebutuhan dan konsumsi energi menyebabkan ketersediaan bahan bakar fosil mulai terbatas. Bagas sorgum manis (Sorghum bicholor L) memiliki kandungan selulosa yang cukup tinggi sehingga berpotensi digunakan sebagai bahan baku untuk produksi bioetanol sebagai bahan bakar alternatif. Penelitian ini bertujuan untuk memproduksi bioetanol dari bagas sorgum manis. Tahapan penelitian meliputi delignifikasi bagas sorgum manis dengan praperlakuan alkali hidrotermal dan H2O2, dilanjutkan dengan Sakarifikasi dan Fermentasi Simultan (SFS), dibandingkan dengan metode Sakarifikasi dan Fermentasi Terpisah (SFT). Konsorsium mikroba yang digunakan adalah kapang Aspergillus niger dan khamir Saccharomyces cerevisiae. Parameter yang dianalisis meliputi total gula, gula pereduksi, kadar etanol, jumlah sel, dan pH. Hasil penelitian menunjukkan nilai konsentrasi etanol tertinggi pada metode SFS yaitu sebesar 4.08 g/L dan laju produksi bioetanol yaitu sebesar 0.06 g/L/jam. Nilai laju pertumbuhan spesifik maksimal untuk jumlah sel (μN maks) dengan metode SFS yaitu sebesar 0.08 jam-1 untuk kapang Aspergillus niger dan 0.14 jam-1 untuk khamir Saccharomyces cerevisiae. Nilai rendemen produk yaitu sebesar 0.23±0.01 g bioetanol/g selulosa. Nilai konsentrasi etanol tertinggi pada metode SFT lebih rendah dibandingkan SFS yaitu sebesar 3.69 g/L dan laju produksi bioetanol yaitu sebesar 0.03 g/L/jam. Nilai laju pertumbuhan spesifik untuk jumlah sel (μN maks) dengan metode SFS yaitu sebesar 0.10 jam-1 untuk kapang Aspergillus niger dan 0.15 jam-1 untuk khamir Saccharomyces cerevisiae. Nilai rendemen produk yaitu sebesar 0.21±0.01 g bioetanol/g selulosa. Penerapan metode SFS mampu meningkatan produksi bioetanol dan memiliki efisiensi lebih tinggi dibandingkan metode SFT.
Keyword: Aspergillus niger, bioetanol, Saccharomyces cerevisiae, Sakarifikasi dan Fermentasi Simultan (SFS), Sakarifikasi dan Fermentasi Terpisah (SFT)

Judul: Posisi Filogenetik Kura-Kura Carettochelys Insculpta  (Reptillia: Testudinata)
Abstrak: Carettochelys insculpta is an endemic freshwater turtle of southern Papua and northern Australia. Phylogenetic position of this turtle is remain unresolved until now. Most of the research conducted show close relationships of C. insculpta and members of Trionychidae family. However, some of the research show distance between C. insculpta and members of Trionychidae family. This research is conducted to analyze phylogenetic relationship between C. insculpta and other members of Testudinata using 12S rRNA, 16S rRNA, and both gene as markers. DNA samples were obtained from three different organisms of C. insculpta. Two species used as outgroups were Alligator mississippiensis and Iguana iguana. Phylogenetic analysis was carried out using Neighbor-Joining method with Felsenstein 1981 (F81) modeltest. A polytomy tree of Testudinata was produced by using 12S rRNA gene. However, analysis using 16S rRNA and both genes as markers confirmed that C. insculpta was located between the Chelonidae and the Trionychidae family.
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