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: Biodelignifikasi Tongkol Jagung Menggunakan Fungi Pelapuk Putih (White Rot Fungi)
Abstrak: Corncob has big potency to be converted become simple sugar such as glucose and xylose which turn can be used as raw material for various products for instance sorbitol and xylitol. Biodelignification is a process to remove lignin and to make fibre free from this subtance by using microorganism like mould, bacteria or enzyme. Delignification need to be done because lignin is main barrier at cellulose hydrolysis process. Some types white rot fungi often applied for delignification are Schizophyllum commune, Phanerochaete chrysosporium and isolate Pleurotus EB9. The aims of this research is to obtain the best type of white rot fungi and to get optimum concentration of mycelial and concentration of glucose which is added and optimum incubation time of chosen best fungi. The result of preliminary research that corncob delignification by fungi Phanerochaete chrysosporium had highest decreasing of lignin content that was 26.07% and degradation of dry weight that is 28.22%. Therefore, Phanerochaete chrysosporium was chosen to be used in main research. Result of main research showed that optimum condition for delignification of corncob by Phanerochaete chrysosporium was incubation time 24.25 days, quantity of mycelial 1.89 ml/10 g substrate and number of glucoses added 0.23 g/10 g substrate. From this condition the value of lignin rate ratio to holocellulose was 0.210689 g/g.
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Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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