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Membrane Microreactor in Biocatalytic Transesterification of Triolein for Biodiesel Production
Achmadin Luthfi Machsun,Misri Gozan,Mohammad Nasikin,Siswa Setyahadi,유영제 한국생물공학회 2010 Biotechnology and Bioprocess Engineering Vol.15 No.6
Transesterification is a principal chemical reaction that occurs in biodiesel production. We developed a novel biocatalytic membrane microreactor (BMM) for continuous transesterification by utilizing an asymmetric membrane as an enzyme-carrier for immobilization. The BMM was developed by pressure driven filtration of lipase from Pseudomonas fluorescens, which is suitable for highly efficient biocatalytic transesterification. Lipase solution was allowed to permeate through an asymmetric membrane with NMWL 300 kDa composed of polyethersulfone. The performances of BMM were studied in biodiesel synthesis via transesterification of triolein with methanol. Transesterification was carried out by passing a solution of triolein and methanol through the asymmetric membrane. The degree of triolein conversion using this microreactor was ca. 80% with a reaction time of 19 min. The BMM system displayed good stability, with no activity decay over a period of 12 day with continuous operation. Results from triolein transesterification clearly demonstrate the potential of an asymmetric membrane as an enzyme carrier material. Enzyme activity (mmol/h·glipase) was approximately 3 fold higher than that of native free lipase.
Wijanarko Anondho,Dianursanti Dianursanti,Gozan Misri,Andika Sang Made Krisna,Widiastuti Paramita,Hermansyah Heri,Witarto Arief Budi,Asami Kazuhiro,Soemantojo Roekmijati Widaningroem,Ohtaguchi Kazuhis The Korean Society for Biotechnology and Bioengine 2006 Biotechnology and Bioprocess Engineering Vol.11 No.6
Alteration of illumination with optimum carbon dioxide fixation-based curve in this research successfully enhanced the $CO_{2}-fixation\;(q_CO_{2}$ capability of Chlorella vulgaris Buitenzorg cultivated in a bubble column photo bioreactor. The level of $CO_{2}$ fixation was up to 1.91 times that observed from cultivation with intensification of illumination on an optimum growth-based curve. During 144 h of cultivation, alteration of light intensity on an optimum $CO_{2}-fixation-based$ curve produced a $q_CO_{2}$ of $12.8\;h^{-1}$. Meanwhile, alteration of light intensity with a growth-based curve only produced a $q_CO_{2}$ of $6.68\;h^{-1}$. Increases in light intensity based on a curve of optimum $CO_{2}-fixation$ produced a final cell concentration of about 5.78 g/L. Both cultivation methods were carried out under ambient pressure at a temperature of $29^{\circ}C$ with a superficial gas velocity of $2.4\;m/h(U_{G}$. Cells were grown on Beneck medium in a 1.0 L Bubble Column Photo bioreactor illuminated by a Phillips Halogen Lamp (20 W/12 V/50 Hz). The inlet gas had a carbon dioxide content of 10%.
L-DOPA Synthesis Using Tyrosinase-immobilized on Electrode Surfaces
( Siti Fauziyah Rahman ),( Siramulu Gobikhrisnan ),( Misri Gozan ),( Gwi Taek Jong ),( Don-hee Park ) 한국화학공학회 2016 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.54 No.6
Levodopa or L-3,4-dihydroxyphenylalanine (L-DOPA) is the direct precursor of the neurotransmitter dopa-mine. L-DOPA is a well-known neuroprotective agent for the treatment of Parkinson`s disease symptoms. L-DOPA was synthesized using the enzyme, tyrosinase, as a biocatalyst for the conversion of L-tyrosine to L-DOPA and an electro-chemical method for reducing L-DOPAquinone, the product resulting from enzymatic synthesis, to L-DOPA. In this study, three electrode systems were used: A glassy carbon electrode (GCE) as working electrode, a platinum, and a Ag/ AgCl electrode as auxiliary and reference electrodes, respectively. GCE has been modified using electropoly-merization of pyrrole to facilitate the electron transfer process and immobilize tyrosinase. Optimum conditions for the electropolymerization modified electrode were a temperature of 30℃ and a pH of 7 producing L-DOPA concentration 0.315 mM. After 40 days, the relative activity of an enzyme for electropolymerization remained 38.6%, respectively.
Effects of magnetic field on calcium carbonate precipitation: Ionic and particle mechanisms
Seung Koo Song,Nelson Saksono,Misri Gozan,Setijo Bismo,Elsa Krisanti,Roekmijati Widaningrum 한국화학공학회 2008 Korean Journal of Chemical Engineering Vol.25 No.5
There are two most widely reported mechanisms to study the effect of magnetic fields on calcium carbonate (CaCO3) precipitate, namely ionic and particle mechanisms. The effects are most debatable because they are contrary to each other. This study explored the effects of both mechanisms in CaCO3 deposit and total CaCO3 precipitation using ionic and particle methods. The ionic method showed reductions in CaCO3 deposit and total precipitation rate of CaCO3, whereas the particle method showed the opposite results. The particle number decreased and the average particle diameter of CaCO3 deposit increased in the ionic method. Meanwhile in the particle method, the particle number increased, average particle diameter decreased and particle aggregation of CaCO3 was observed. XRD measurement on all deposits showed that the crystal deposit was mostly of calcite and the traces of vaterite. However, the amount of the crystal in the particle method was observed to be less than that in the ionic method, indicating that CaCO3 deposit was more amorphous. Particle mechanism decreased the Ca2+ ion concentration in solution during magnetization, and ionic mechanism reduced scale (CaCO3) formation after magnetization and separation processes. This method could be applied for decreasing water hardness and prevent the formation of scaling.