Judul: Isolasi dan Pencirian Xilanase dari Bakteri Asal Tanah Taman Nasional Bukit Duabelas, Jambi, Indonesia
Abstrak: Xilanase merupakan enzim pendegradasi xilan yang berguna dalam penyempurnaan biokonversi biomassa lignoselulosa menjadi produk bermanfaat. Aplikasi xilanase yang luas belum dioptimalkan karena kurang tersedianya mikroba unggul. Penelitian ini bertujuan untuk mengisolasi bakteri asal tanah hutan Taman Nasional Bukit Duabelas, Jambi dan mencirikan xilanasenya yang meliputi parameter pH optimum, suhu optimum, serta stabilitasnya. Sebanyak 28 isolat potensial telah berhasil diisolasi dari tanah hutan Taman Nasional Bukit Duabelas, Jambi dan tiga di antaranya berhasil dicirikan xilanasenya (isolat 10, 18, dan 27). Isolat 10 memproduksi xilanase ekstraseluler tertinggi pada jam ke-12 dan jam ke- 36 inkubasi kultur dengan aktivitas optimum pada pH 6 di suhu 40 oC dan 90 oC. Waktu produksi xilanase tertinggi isolat 27 tercapai pada jam ke-12 dan jam ke-30 inkubasi kultur. Kondisi optimum xilanase isolat 27 terjadi pada pH 5 di suhu 90 oC dan 50 oC, sementara xilanase isolat 18 mencapai waktu optimum produksi pada jam ke-18 dan jam ke-36 inkubasi kultur. Kondisi optimum xilanase isolat 18 tercapai pada pH 5 dan suhu 90 oC. Enzim isolat 18 memiliki waktu paruh 1 jam 7 menit pada pH dan suhu optimumnya
Keyword: Bogor Agricultural University, Institut Pertanian Bogor, IPB, Xylanolitic, Xylanase, Bukit Duabelas National Park, Jambi

Judul: Isolasi dan Pencirian Xilanase dari Bakteri Asal Tanah Hutan Taman Nasional Bukit Duabelas, Jambi, Indonesia
Abstrak: Xylanase is a xylan-degrading enzymes which are useful to improving the bioconversion of lignocellulosic biomass into useful products. Broad application of xylanase have not optimized due to the lack of superior microbes. The aim of this study is to isolate bacterial origin Bukit Duabelas National Park, Jambi and characterize its xylanase, including its pH optimum, temperature optimum, and stability. A total of 28 potential isolates have been isolated from Bukit Duabelas National Park soil, Jambi and three were successfully characterized its xilanase (isolates 10, 18, and 27). Isolate 10 reached the highest producing extracellular xylanase at 12th and 36th hours of culture incubation with optimum activity at pH 6, temperature 40 °C and 90 oC. Isolate 27 reached its highest producing extracellular xylanase at 12th and 30th hours of culture incubation. The optimum condition of xylanase isolate 27 occurred at pH 5, temperature 90 oC and 50 oC, while xylanase isolate 18 achieve its optimum production time at the 18th and 36th hours of incubation culture. Xylanase isolate 18 achieved its optimum condition at pH 5 and temperature 90 oC and has half-life time 1 hour 7 minutes.
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Judul: Tinjauan Matematis pada Model Makroskopik dan Mikroskopik Arus Lalu-lintas
Abstrak: Traffic flow phenomenon can be described through mathematical model such as continuous dynamic model with an ordinary differential equation so that it can be solved with integral factors. In this paper three simple models of traffic flow are discussed, i.e, two macroscopic and one microscopic models. Macroscopic model formulates dynamics of the traffic flow that occurs on a large number of vehicles on a road. While the microscopic model explains drivers’ behavior in their interaction with other vehicles ahead, i.e, car-following model. This paper shows the existence of ordinary differential equation found in the traffic flow model and indicates some different representations in the context of the same model. It also reviews a simple model of traffic flow along a single link, which leads to some unexpected results, i.e, it can express the solution model in term of link outflows as well as trip time. In the microscopic model, simulation is done to illustrate the behavior of the drivers with a sensitivity coefficient as a benchmark parameter.
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