Judul: Kajian Hidrolisis Tongkol Jagung oleh Kapang Selulolitik Menggunakan Kultivasi Media Padat untuk Produksi Pakan
Abstrak: Corn (Zea mays L.) is one of the main food crops in the world. Most of corn use as raw material for food and non-food industries. But these applications are limited to the corn kernel, and other parts of corn plant were not utilized yet. Among the available agricultural products, corncob is an abundant lignocellulosic raw materials and potential sources for feed in Indonesia. Corncob utilization for feed has been conducted for years, although it is limited as fiber source. High amount of lignocellulosic compound affects low digestibility of corncob. Biological process can be used to improve the nutritional value corncob, which can impact to the feed availability during the dry season. The objective of this research was to improve the nutrition value of corncob through fungal cellulolytic hydrolysis by using solid-state cultivation. Trichoderma viride and Rhizopus oryzae were used as fungal cellulolytic microorganisms which were cultivated in different bed thickness (2 and 4 cm) and mixing treatment (intermittent mixing every 3 days, and no mixing). Inocula were prepared from 7 days-old of fungi slant and grown on rice bran flour for 10 days. The process was conducted for 15 days, and the cultures were monitored every 3 days. The changes on chemical composition (moisture, fiber, protein, reducing sugar, and total sugar), pH value, and loss weight of the substrate. In the final cultivation, the products were analyzed as in vitro digestibility, the changes of fiber structure by using microscopic examination. T. viride caused low moisture content (10%) remained on the substrate in the end of cultivation; while in inverse fact was to R. oryzae (91%). Cellulolytic enzymes acts on corncob accumulated the total and reducing sugar content, and produced cello-oligosaccharides which functioned as prebiotic for ruminant animal. In vitro digestibility of the products from both fungal, bed thickness and mixing treatments also showed insignificantly effects. Since it was very long cultivation process caused the available nutritional value were re-used for fungal metabolism.
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Judul: Pengaruh Delignifikasi Menggunakan Phanerochaete chrysosporium dan Hidrolisis oleh Kapang Selulolitik terhadap Kualitas Tongkol Jagung sebagai Pakan Ternak
Abstrak: Concorb was one of the agricultural waste that has potency for ruminant feed. Concorb has high fiber content, but it has limited application since its low digestibility and protein content. Lignin in corncob should be liberate from cellulose and hemicellulose in the fiber substances. This research used white-root fungus of Phanerochaete chrysosporium for delignification and fungi Aspergillus niger and Trichoderma viride for hydrolysis the delignified corncob to increase its digestibility as feed. Urea and ammonium sulphate were added to enrich the corncob during hydrolysis in solid-state cultivation. After 20 days of biodelignification, 17.76 % of lignin was removed. Cultivation of delignified corncob by cellulolytic fungi increased the total and reducing sugar contents. The best hydrolysis treatment obtained from T. viride enriched with ammonium sulphate while A. niger with urea. T. viride increased 14.11 % of dry matter and 13.76 % of organic matter digestibilities. A. niger increased 15.03 % of dry matter and 8.11 % of organic matter digestibilities. Increasing of oligosacaride content made hydrolized corncob as prebiotic for better feed quality. Mixing isolates between A. niger and T. viride hydrolysis is expected to give better results in next research.
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Judul: Teknik penentuan posisi bintang berdasarkan pelat foto overlapping
Abstrak: Bintang adalah salah satu objek langit yang menarik untuk diamati. Untuk itu, pengetahuan tentang posisi bintang sangat diperlukan. Posisi bintang di langit dapat dihitung melalui foto bintang. Fotografi astronomi atau astrometri merupakan ilmu yang mempelajari metode untuk menentukan posisi bendabenda langit seperti bintang berdasarkan pelat foto (Kamp, 1967). Sebuah pelat foto berisi citra bintang-bintang yang sudah diketahui posisinya berdasarkan katalog dan citra bintang-bintang yang belum diketahui posisinya. Posisi bintang yang ada di katalog dinyatakan dengan (a,3). Bintang yang belum diketahui posisinya lebih banyak jumlahnya daripada bintang yang sudah diketahui posisinya. Citra bintang pada pelat foto berupa sebuah titik dalam bentuk tetap. Posisinya pada pelat merupakan hasil pengukuran pada bidang kartesius dan dinyatakan dengan (1;,fl). Hasil pengukuran tersebut kemudian direduksi menjadi koordinat terukur (x,y). Hubungan antara (a,3) dan (x,y) didekati dengan sebuah deret dengan konstanta-konsranta deret merupakan konstanta pelat. Nilai konstanta pelat diperoleh dengan menggabungkan hasil pengukuran posisi bintang pada masing-masing pelat menjadi sebuah persamaan normal (Jefferys, 1963). Hasil akhir dari gugus persamaan normal tersebut dijabarkan dalam bentuk nOlasi matriks partisi dan berupa sebuah sistem persamaan linier Ax = b di mana A adalah matriks jarang, dan x merupakan konstanta pelar yang akan dicari nilainya. Untuk menyelesaikan sistem persamaan linier terse but digunakan metode transformasi given. Konstanta pelat yang sudah diperoleh dengan menyelesaikan sistem persamaan linier di atas, kemudian disubtitusi ke sebuah persamaan untuk memperoleh posisi bintang yang tidak tercantum dalam katalog. .
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