Judul: Pengaruh lama penyimpanan terhadap kualitas inokulum Trichoderma viride dan Rhizopus oryzae untuk hidrolisis tongkol jagung
Abstrak: Kapang selulolitik merupakan jenis kapang yang memiliki kemampuan untuk mensintesis enzim selulase yang mampu menghidrolisis bagian selulosa yang terikat kuat dengan ikatan hidrogen. Kapang Trichoderma viride diisolasi dari tanah dan mempunyai enzim selulase lengkap yang dibutuhkan untuk hidrolisis selulosa. Kapang lain yang mempunyai kemampuan selulolitik adalah Rhizopus oryzae yang mempunyai kemampuan untuk mengubah pati menjadi dekstrosa serta dapat memecah protein dan lemak sehingga biasanya digunakan untuk memproduksi enzim amilase, protease maupun untuk menghasilkan tempe. Untuk mempermudah pemanfaatan kapang selulolitik di masyarakat perlu dilakukan pembuatan inokulum kapang. Inokulum yang dihasilkan harus memiliki viabilitas spora kapang yang tinggi dan cenderung stabil selama inokulum tersebut disimpan serta memiliki kemampuan hidrolisis yang tinggi terhadap tongkol jagung. Tongkol jagung merupakan salah satu limbah industri pertanian yang merupakan sumber bahan berlignoselulosa, dengan kandungan selulosa 40-60% dan hemiselulosa 20-30% sehingga tongkol jagung mempunyai potensi yang besar dihidrolisis oleh kapang yang mempunyai enzim selulolitik dan dimanfaatkan sebagai bahan pakan.
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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: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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