Judul: Penapisan Bakteri Lipolitik asal Fruktosfer Kelapa Sawit
Abstrak: Lipase (EC 3.1.1.3, glycerol ester hidrolase) is defined as carboxylesterase that catalyzes the hydrolysis of long chain asilgliserol. Lipase produced by lipolytic bacteria that grow well in substrates containing oils such as oil palm fruit. The purpose of this study was to screen lipolytic bacteria from oil palm fructosphere and to characterize optimal pH and temperature of lipase enzyme from selected isolates. Seven isolates of lipolytic bacteria with different morphology were qualitatively screened from oil palm fructosphere using Rhodamin B media. Bacteria were isolated from the exocarp and mesocarp of ripe oil palm fruits. Lipolytic activity each isolates were measured and selected based on their activity. Three isolates possessed the best activity with result as follows EP2.22 (0.912 U/mg), F2 (0.792 U/mg), and F6 (0.650 U/mg). These isolates showed high activity at various range of pH and temperature. Isolate EP2.22 showed optimum pH at 7.5 and optimum temperature at either 40 oC or 70 oC. Isolate F2 showed optimum pH 8.5 and optimum temperature 70 oC. Isolate F6 showed optimum pH 8.5 and optimum temperature at 30 oC and 70 oC. Two peaks of high activity due to the use of crude enzyme extract. 16S rRNA gene sequencing indicated that isolates EP2.22, F2, and F6 closely related to Staphylococcus klosii Enterobacter sp., and Buttiauxella izardii.
Keyword: 

Judul: Isolasi dan Identifikasi Bakteri Termofilik Penghasil Selulase dari Kelapa Sawit (Elaeis guineensis)
Abstrak: Cellulase is an enzyme catalyzing hydrolysis of cellulose which usually consists of endoglucanases (EC.3.2.1.4), exoglucanases (EC.3.2.1.91) and β-glucosidases (EC.3.2.1.21). Cellulase is a very important enzyme due to its numerous industrial applications. The aim of this research were to isolate and identify cellulase-producing thermophilic bacteria that can be used to increase value added in oil palm industries. Samples of soil, empty fruit bunch compost and palm kernel meal were collected from oil palm plantation for obtained thermophilic bacteria. The samples were screened of cellulase-producing thermophilic bacteria by using a Congo Red method were made on carboxymethyl cellulose (CMC) agar plates. The bacterial cultures were incubated in a shaking incubator (140 rpm) at 50oC for 24 hours. The assay for the enzymatic activity was based on the release of glucose that was detected using 3,5-dinitrosalicylic acid (DNS). In this research, 19 isolates of bacteria were isolated. It was found that 11 isolates of bacteria showed positive results with clear zone around the cultures by using Congo Red method. The result showed that isolates for CK1, EM4 and CK3 possesed the highest enzyme activity of 13.56, 12.50 and 10.49 U mL-1 for cellulase was detected at pH 7, respectively. The results of strain identification based on 16S rRNA showed that strain CK1, EM4 and CK3 were identified as Bacillus subtilis.
Keyword: 

Judul: Pengaruh panjang deret waktu data terhadap perhitungan debit banjir rencana
Abstrak: Dalam perencanaan bangunan air, harus ditunjang oleh data yang lengkap. Pada kenyataannya data yang lengkap dewasa ini sulit diperoleh. Selain itu pengambilan data ini memerlukan waktu, ketepatan, ketelitian serta biaya yang cukup besar. Tujuan dari penelitian ini adalah mempelajari pengaruh panjang data terhadap perhitungan banjir rencana, menentukan besarnya banjir maksimum yang akan terjadi untuk periode waktu yang berbeda, serta menentukan distribusi banjir teoritis yang paling sesuai pada daerah yang diteliti. Menurut Chow (1964), di dalam analisa hidrologi digunakan asumsi bahwa kejadian-kejadian selama pengamatan cukup mewakili dan hasil pengamatan tersebut dapat dipercaya. Kepercayaan semakin meningkat dengan bertambah lamanya pencatatan data. Dalam kenyataannya, lama pencatatan data yang dilakukan tergantung dari periode ulang yang akan digunakan dalam mendesain suatu bangunan. Menduga suatu kejadian dengan periode ulang yang lebih besar daripada periode pencatatan menyebabkan hasil pendugaan tidak dapat dipercaya....
Keyword: