Judul: Karakteristik Enzim Mananase Isolat Aktinomisetes dari Taman Nasional Bukit Duabelas Jambi
Abstrak: Indonesia memiliki sekitar 14.03 juta ha perkebunan kelapa sawit. Bungkil inti sawit (BIS) merupakan produk samping hasil pengolahan minyak sawit yang terdiri atas β-manan. Manan adalah komponen hemiselulosa yang memiliki nilai ekonomi. Manan dapat dikonversi menjadi manooligosakarida (MOS) menggunakan bakteri melalui proses enzimatik. Tujuan dari penelitian ini adalah mengetahui karakteristik enzim mananase dari isolat aktinomisetes asal Taman Nasional Bukit Duabelas Jambi. Penapisan dimulai dengan seleksi pembentukan zona bening pada media yang mengandung BIS kemudian diukur aktivitas enzimnya serta dikarakteristik pH dan suhu optimum aktivitas enzim. Isolat HJ4-5B memiliki indeks mananolitik tertinggi sebesar 0.4. Isolat HJ4-5B memiliki satu puncak aktivitas enzim pada hari ke-7 inkubasi sebesar 0.895 U/mL. Aktivitas mananase isolat HJ4-5B tertinggi pada pH 6 dan suhu 70 °C dengan waktu inkubasi selama 7 hari adalah 1.186 U/mL.
Keyword: aktivitas enzim, bungkil inti sawit, mananolitik, manooligosakarida

Judul: Isolasi dan Pencirian Bakteri Mananolitik Pendegradasi Bungkil Inti Sawit
Abstrak: Mannanase is an enzyme which can be utilized in food and feed sector. This research is aimed to isolate and characterize the mannanase producing soil bacteria from palm plantations in Cikasungka, Bogor, and to know the ability of manannase in hydrolyzing palm kernel cake (PKC) substrate become to manno-oligosaccharide (MOS). There were 8 isolates isolated from the soil of Cikasungka Plantation, Bogor. Three isolates were choosen with the highest mannanolytic index to be further characterized. Isolate 5 produced the highest mannanase activity at 18 h of incubation (0.039 U/mL) and 54 h (0.051 U/mL). Isolate 6 produced the highest mannanase activity at 30 h of incubation (0.041 U/mL) and 66 h (0.058 U/mL). Isolate 7 produced the highest mannanase activity at 24 h of incubation (0.041 U/mL). The specific activity of isolate 5, 6 and 7 had value 2-3 times higher than their own enzymatic activity. One selected isolate, isolate 6 had optimum activity in pH 5.5 at 30 °C and pH 7 at 40 °C. The enzyme stability of isolate 6 were decreasing at the both pH and temperature optimum. The polimerization degree of isolate 6 in pH 5.5 at 30 °C had value of 4.0-4.1 and 6.9-7.5 in pH 7 at 40 °C. Isolate 6 posseses high degree of polimerization in MOS production, it is potentially used as cattle prebiotic.
Keyword: mannanase, mannanolytic, manno-oligosaccharide, palm kernel cake, polimerization degree

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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