Judul: Weak Acid Hydrothermal in Oil Palm Empty Fruit Bunch Biodegradation by Trametes hirsuta EDN 082
Abstrak: Proses produksi bioetanol dari konversi lignoselulosa menghadapi beberapa permasalahan agar lebih komersial dan rendah biaya. Kandungan lignin adalah faktor yang paling signifikan terhadap tingginya biaya konversi biomasa lignoselulosa.. Proses delignifikasi telah banyak dilakukan menggunakan zat kimia, seperti menggunakan asam/basa lemah. Delignifikasi kimiawi efektif dalam memutus ikatan lignin, namun akan menghasilkan senyawa samping berupa hidroksi metil furfural (HMF). HMF akan menghambat khamir dalam proses fermentasi untuk produksi bioetanol. Penyelesaian dari masalah tersebut ialah dengan delignifikasi secara biologi (biodelignifikasi). Biodelignifikasi dilakukan menggunakan jamur pelapuk putih (JPP) yang dapat menghasilkan beberapa enzim lignoselulolitik, salah satunya ialah lakase. Trametes hirsuta merupakan salah satu jenis JPP. Penelitian dimulai dengan persiapan biomassa lignoselulosa berupa serbuk tandan kosong kelapa sawit (TKKS) yang diayak berukuran 40-60 mesh, serta persiapan inokulum yang ditumbuhkan pada media cair Potato Dextrose Broth (PDB) selama 7 hari. Degradasi lignoselulosa dilakukan dengan praperlakuan hidrotermal dan biologis. Pengujian yang dilakukan meliputi kadar lignin dan komponen kimia lainnya. Pengamatan perubahan morfologi dari TKKS dilakukan menggunakan Scanning Electron Microscope (SEM), sedangkan perubahan struktur kimia diamati menggunakan Fourier Transform Infra Red (FTIR), Pyrolysis Gas Chromatography-Mass Spectrometry (Py-GC/MS), dan X-Ray Diffraction (XRD). Hasil pengujian kadar lignin setelah degradasi menunjukkan penurunan jumlah total lignin. Perlakuan T. hirsuta efektif menghilangkan total kehilangan padatan sampai 80%. Perlakuan JC (Kontrol dan T. hirsuta) dan JW (Hidotermal air dan T. hirsuta) mempertahankan selulosa dan hemiselulosa lebih baik daripada JOA (Hidrotermal asam dan T. hirsuta). Hasil analisis FTIR menunjukkan bahwa praperlakuan dengan jamur menyebabkan penurunan intensitas, yang mengindikasikan adanya pengurangan ikatan-ikatan hidrogen. Analisis Py-GC/MS menunjukkan produk degradasi dari biomassa TKKS seperti phenol, creosol, 2,6-dimethoxy phenol, benzene, benzaldehyde, trans-isogeunol, syringalacetone, dan ethenone. SEM menunjukkan perubahan morfologi permukaan TKKS yang telah diberi jamur (JC, JW, JOA) memiliki permukaan yang kasar dan terbelah-belah, sebagian diikuti oleh pertumbuhan miselium di bagian luar dan menembus bagian dalam. Hasil analisis kristalinitas TKKS yang diberi praperlakuan hidrotermal (W, OA) memperlihatkan adanya kenaikan indeks kristalinitas, sedangkan perlakuan biologis dengan jamur (JC, JW, JOA) menunjukkan adanya penurunan indeks kristalitinas. Berdasarkan semua analisis yang digunakan pada penelitian ini, perlakuan JC berpotensi untuk delignifikasi lebih baik dan ramah lingkungan.
Keyword: Lignocellulosic biomass, Lignocellulosic degradation, Oxalic acid hydrothermal, Water hydrothermal, White-rot fungi

Judul: Optimasi Proses Hidrolisis Kimiawi dan Enzimatis Tandan Kosong Kelapa Sawit Menjadi Glukosa untuk Produksi Etanol
Abstrak: Recently, energy especially from petroleum fuel become a serious problem for the whole countries in the world, including Indonesia. Decreasing world’s petroleum stock make its price is very high. So, it is urgent to search other alternative energy sources, such as bioethanol. Oil Palm Empty Bunches (OPEB) are found abundantly as waste of CPO production. It is rich in lignocellulose content. After delignification by white rot fungi Omphalina sp, cellulose from OPEB can be degraded to glucose as the raw material for etanol production by hydrolysis process. In this research, hydrolysis were done chemically using H2SO4 and HCl and enzymatically using cellulolytic bacteria and Trichoderma isolates. Chemical hydrolysis was carried out in autoclave at temperature of 121oC and varation in acid concentration (0.1N; 0.5N; 1N; and 2N) and hydrolysis time (20; 40; 60; 120; and 240 min). The condition was then reoptimalized by increasing the temperature to 200 0C and variation hydrolisis time (5;7,5;10;12,5; dan 15 min). Enzymatic hydrolysis were done by two methods, namely simultaneuos and separated bacth methods using Trichoderma or cellulolytic bacteria and Saccharomyces cereviceae. Delignification process increased cellulose content from 47.18% to 49.09%. The optimum condition by chemical hydrolisis with H2SO4 2N was resulted in sugar content (30,86%) with ethanol production 1.82%. By enzymatic methods, higher sugar content was obtained by Trichoderma isolate with incubation time 72 hours. The sugar content was 1.46 g/L and ethanol production was 0.33%. Ethanol production from simultaneuos process by cellulolytic bacteria was the same as ethanol production from Trichoderma by separated batch process i.e as much as 0.27 %
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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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