Misri Gozan
Department of Chemical Engineering, Faculty of Engineering, University of Indonesia, Depok 16424, Indonesia

Published : 6 Documents
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TECHNIQUE FOR IMMOBILIZATION OF LIPASE WITHIN MEMBRANE PORES AS NANOREACTOR

Jurnal Sains Materi Indonesia Vol 12, No 3 (2011): Juni 2011
Publisher : BATAN

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Abstract

The objective of this study was to design of nanoscale biocatalyst system by utilizing the membrane as nanoporous media. The nanostructure was modified by two step methods: simple adsorption and continue with pressure driven filtration. Two types of polymeric membranes Mixed Cellulose Ester (MCE) and Polyethersulfone (PES) were used asmatrices for immobilization of lipase from Pseudomonas fluorescens. The lipase solution was allowed to permeate through the membrane and lipase molecule adsorbed on the inner wall of pores. The porosity and membrane matrices influenced the enzyme loading. The best result for enzyme loading inmembrane matric is 3.75 g.m-2 using PES membrane with incubation time of 18 hours. PES membrane was selected for further continuous transesterification studies. We evaluated the transesterification activity by converting triolein and methanol to methyl oleate and glycerol. The reaction was carried out in situ within the pores of membrane matric, so that its pores act kind of nanoreactor during formation of product material. The degree of triolein conversion using this kind of nanoreactor was about 80% with 30 minutes of residence time. The productivity of immobilized lipase within the pores were 40 fold higher than that of native free lipase.Keywords: Biocatalyst, Lipase, Membrane, Transesterification, Immobilization.

Utilization of Bagasse Cellulose for Ethanol Production through Simultaneous Saccharification and Fermentation by Xylanase

Makara Journal of Technology Vol 11, No 1 (2007)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

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Abstract

Bagasse is a solid residue from sugar cane process, which is not many use it for some product which have more added value. Bagasse, which is a lignosellulosic material, be able to be use for alternative energy resources like bioethanol or biogas. With renewable energy resources a crisis of energy in Republic of Indonesia could be solved, especially in oil and gas. This research has done the conversion of bagasse to bioethanol with xylanase enzyme. The result show that bagasse contains of 52,7% cellulose, 20% hemicelluloses, and 24,2% lignin. Xylanase enzyme and Saccharomyces cerevisiae was used to hydrolyse and fermentation in SSF process. Variation in this research use pH (4, 4,5, and 5), for increasing ethanol quantity, SSF process was done by added chloride acid (HCl) with concentration 0.5% and 1% (v/v) and also pre-treatment with white rot fungi such as Lentinus edodes (L.edodes) as long 4 weeks. The SSF process was done with 24, 48, 72, and 96 hours incubation time for fermentation. Variation of pH 4, 4,5, and 5 can produce ethanol with concentrations 2,357 g/L, 2,451 g/L, 2,709 g/L. The added chloride acid (HCl) with concentration 0.5% and 1% (v/v) and L. edodes can increase ethanol yield, The highest ethanol concentration with added chloride acid (HCl) concentration 0.5% and 1% consecutively is 2,967 g/L, 3,249 g/L. The highest ethanol concentration with pre-treatment by L. edodes is 3,202 g/L.

Kinetic Model For Triglyceride Hydrolysis Using Lipase:Review

Makara Journal of Technology Vol 11, No 1 (2007)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

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Abstract

Triglyceride hydrolysis using lipase has been proposed as a novel method to produce raw materials in food and cosmetic industries such as diacylglycerol, monoacylglycerol, glycerol and fatty acid. In order to design a reactor for utilizing this reaction on industrial scale, constructing a kinetic model is important. Since the substrates are oil and water, the hydrolysis takes place at oil-water interface. Furthermore, the triglyceride has three ester bonds, so that the hydrolysis stepwise proceeds. Thus, the reaction mechanism is very complicated. The difference between the interfacial and bulk concentrations of the enzyme, substrates and products, and the interfacial enzymatic reaction mechanism should be considered in the model.

Biomass Production Chlorella Vulgaris Buitenzorg Using Series of Bubble Column Photo Bioreactor with a Periodic Illumination

Makara Journal of Technology Vol 12, No 1 (2008)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

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Abstract

Chlorella vulgaris Buitenzorg cultivation using three bubble column photo bioreactors arranged in series with a volume of 200 mL for 130 hours shows an increase of biomass production of Chlorella vulgaris Buitenzorg up to 1.20 times and a decrease of the ability of CO2 fixation compared to single reactor at a periodic sun illumination cycle. The operation conditions on cultivation are as following: T, 29.0oC; P,1 atm.; UG, 2.40 m/h; CO2, 10%; Benneck medium; and illumination source by Phillip Halogen Lamp 20W /12V/ 50Hz. Other research parameters such as microbial carbon dioxide transferred rate (qco2), CO2 transferred rate (CTR), energy consumption for cellular formation (Ex), and cultural bicarbonate species concentration [HCO3] also give better results on series of reactor.

TEKNIK AMOBILISASI LIPASE DIDALAM PORI-PORI MEMBRAN POLIMER SEBAGAI NANOREAKTOR

Jurnal Sains Materi Indonesia Vol 12, No 3: Juni 2011
Publisher : BATAN

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Abstract

TEKNIK AMOBILISASI LIPASE DIDALAM PORI-PORI MEMBRAN POLIMER SEBAGAI NANOREAKTOR. Penelitian ini bertujuan untuk merancang sistem nanoreaktor dengan memanfaatkan membran sebagai media nanopori. Struktur nano tersebut dikembangkan dengan metode dua tahap: adsorpsi sederhana dan dilanjutkan dengan filtrasi bertekanan. Dua tipe membran polimer yaitu Mixed Cellulose Ester(MCE) dan Polyethersulfone (PES) digunakan sebagai matriks untuk amobilisasi lipase dari Pseudomonas fluorescens. Larutan lipase mengalir melalui membran dan molekul lipase teradsorpsi pada dinding pori. Porositas dan matriks membran berpengaruh terhadap nilai enzyme loading. Penggunaan membran PES dengan waktu inkubasi 18 jam menghasilkan nilai enzyme loading paling besar yaitu 3,75 g/m2. Selanjutnya membran PES dipilih untuk studi transesterifikasi kontinyu. Dievaluasi aktifitas transesterifikasi dengan mengkonversi triolein dan metanol menjadi metil oleat dan gliserol. Reaksi dilakukan secara in situ di dalam pori-pori membran yang berperan sebagai reaktor. Nilai derajat konversi triolein dengan menggunakan nanoreaktor ini sekitar 80 % dengan waktu tinggal 30 menit. Produktifitas lipase amobil di dalam pori 40 kali lipat lebih tinggi dibandingkan lipase free.

PERILAKU HOMOSEKSUAL: MENCARI AKAR PADA FAKTOR GENETIK

Nizham Jurnal Studi Keislaman Vol 4 No 1 (2016): Islam dan LGBT
Publisher : Post Graduate Programe of State Institute of Islamic Studies Metro – Lampung

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Abstract

The study based on literatures on this article presents data that is critical discourses of homosexuality and genetics. This article does not disclose the direction of Islam in terms of homosexuality because it is so obvious expressed in the Koran and explained by the righteous mufassir, muslim clerics and scholars. There is no strong data linking specific genetic factors with the emergence of homosexual behavior. Research conducted by the proponents of homosexual showed no single gene that govern human behavior which is a very complex phenomena. In other words, the genes do not determine behavior of homosexuality in particular. Expressed genes responsible for the nature of homosexuality is also interpreted as genes responsible for other mental problems. The experts further revealed that homosexual orientation is strongly affected by the events and stimuli experienced by either of the environment with a growing degree of openness to homosexual behavior as well as due to the availability of information, especially in cyberspace. Some chemicals are suspected of causing physical changes and influence on sexual orientation. Efforts of healing through action or medical intervention are not  impossible. Some researches suggest that homosexual behavior is more aggressive than men hetersexual both in individual and family scale. The author sees the belief that genetic factors are the reason for accepting homosexual behavior has no strong scientific roots. Behavior of homosexuality thus can actually be, or should be, repaired and healed.