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"Synthetic biodiesel using biocatalyst is an emerging and attracting alternative process to replace the conventional process. However, biocatalyst is easy to be deactivated by alcohol, which is a reactant in biodiesel synthesis reaction. Therefore, it is needed to develop new method to maintain the activity and stability of the biocatalyst during reaction. New method to be developed is by changing the reaction route which is using alcohol to the reaction route which is not using alcohol. Route reaction of non alcohol can be done by changing the alkyl alcohol with alkyl acetate. Both have the same function as alkyl supply during the reaction. In this paper, the research results of the synthesis biodiesel via route of non alcohol using biocatalyst Novozym 435 are presented In this reaction, methyl acetate is reacted with triglyceride from used fried oil in batch reactor. The reactants and products were analyzed using HPLC. The Results showed that Novozym 435 can convert trioleat up to 93.24% under the condition of 4% wt substrate of the biocatalyst concentration, oil/alkyl mole ratio equal to 1/I2 in 50 hour reaction. Stability test indicate that the activity of the immobilized biocatalyst still remain after three reaction cycles."

"Skripsi ini menyajikan hasil penelitian penurunan dan estimasi konstanta model kinetika berbasis ping-pong bibi untuk sintesis biodiesel menggunakan Porcine Pancreatic Lipase. Penelitian dilakukan dengan penyusunan tiga model matematis menyeluruh berbasis ping-pong bibi yang mampu mendeskripsikan perilaku setiap komponen reaktan dan produk yang terlibat. Konstanta kinetika dari model yang didapat, diestimasi secara numerik. Hasil penelitian ini menunjukkan bahwa model kinetika berbasis ping-pong bi bi adsorpsi paling baik dalam mendeskripsikan perilaku reaksi setiap elemen reaktan produk dari reaksi interesterfikasi trigliserida dengan Porcine pancreatic lipase tersuspensi dan terimmobilisasi dengan jumlah kuadrat error relatif masing-masing sebesar 2,61 dan 1,46.

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In this paper, three different mathematical model based on Ping Pong Bi Bi mechanism was presented on biodiesel synthesis. Validity of the three models was tested by fitting on experimental data resulted from biodiesel synthesis via non-alcoholic route using Porcine Pancreatic Lipase. The kinetic constants from the model were estimated by numerical analysis.

The experimental result showed that the present model gave better fitted result and well described the entire component involved in interesterification reaction using free and immobilized Porcine Pancreatic Lipase with the squared-sum of relative error 2.61 and 1.46 respectively."

"Mengkonsumsi minyak diasilgliserol (DAG) dapat mencegah akumulasi lemak dan obesitas. Penelitian ini meneliti tentang teknologi produksi minyak DAG satu tahap dari minyak kelapa sawit menggunakan kombinasi parsial hidrolisis dan parsial esterifikasi menggunakan biokatalis terimmobilisasi di dalam sebuah bioreaktor hollow fiber membran. Hasil dari reaksi parsial hidrolisis digunakan sebagai umpan reaksi parsial esterifikasi untuk meningkatkan yield minyak DAG. Pengaruh konfigurasi arah aliran minyak dalam sintesis tidak signifikan. Semakin besar konsentrasi enzim yang digunakan, meningkatkan yield minyak DAG yang dihasilkan. Melalui studi laju alir minyak, diperoleh bahwa pada konsentrasi biokatalis 5 mg/mL dan laju alir optimum 0,05 mL/ dihasilkan minyak DAG dengan kemurnian 79,19%.

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Consumption of Diacylglycerol (DAG) oil can prevent fat accumulation and obesity. This research investigated one step DAG oil production technology from palm oil by a combination of the partial hydrolysis and partial esterification reaction using immobilized biocatalyst in a hollow fiber membrane bioreactor.

The result of partial hydrolysis is used to be the feed of partial esterification reaction to increase the yield of DAG oil. The effect of configuration of oil flow direction in the synthesis process is not significant. Higher enzyme concentration increased the yield of DAG oil produced. Through the study of oil flow rate, obtained that by using 5 mg/mL biocatalyst concentration and 0,05 mL/s as optimum flow rate can produce 79,19% DAG Oil purity."

"Studi tentang biotransformasi asetonitril menggunakan bakteri Gram positif yang diisolasi dari sedimen sungai yang sudah tercemar limbah industri di kawasan Cibinong, Jawa Barat telah dilakukan. Sebanyak 200 isolat bakteri telah diskrining aktivitasnya dalam mendegradasi senyawa nitril, dan didapatkan 2 isolat unggulan yaitu isolat 100A dan 100D. Hasil skrining pada medium mineral yang mengandung asetonitril dengan konsentrasi 100 mM, menunjukkan indikasi kuat bahwa bakteri tersebut mampu menghasilkan enzim nitril hidratase dan amidase. Akan tetapi, kedua bakteri tersebut tidak mampu tumbuh pada media yang mengandung benzonitril. Hasil ini didukung dengan data karakterisasi secara molekuler dengan menggunakan primer spesifik, dimana isolat 100A dan 100D secara positif mengandung gen penyandi α-nitril hidratase dan amidase. Pada posisi pertama susunan asam amino dari gen penyandi α-nitril hidratase terdapat perbedaan antara isolat 100A (Methionine 1) dan 100D (Glycine 1). Hasil identifikasi berdasarkan analisis filogenetik menggunakan sekuen 16S ribosomal DNA menunjukkan bahwa kedua bakteri ini memiliki kekerabatan yang sangat dekat dengan Rhodococcus qingshengii, R. baikonurensis dan R. erythropolis. Analisis pairwise nucleotide alignment menunjukkan bakteri 100A dan 100D memiliki susunan nukleotida yang lebih mirip dengan R. qingshengii, sehingga kedua isolat bakteri tersebut diberi nama Rhodococcus aff. qingshengii 100A dan Rhodococcus aff. qingshengii 100D.

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Study of the biotransformation of acetonitrile using Gram-positive bacteria isolated from sediment of industrial waste contaminated river in Cibinong, West Java has been carried out. A total of 200 bacterial isolates were screened for their activity in degrading nitrile compounds of which two isolates with highest activity were selected for the molecular characterization. Screening of nitrile degrading enzymes using mineral medium 100 mM acetonitrile showed that isolates 100A and 100D capable of producing α-nitrile hidratase and amidase enzymes. However, both bacteria are unable to grow on media containing benzonitrile. These results were supported by molecular characterization using specific primers, where isolates100A and 100D positively contain genes encoding α-nitrile hidratase and amidase. There was a difference at the first position of amino acid composition of the gene encoding α-nitrile hidratase between isolates 100A (Methionine1) and 100D (Glycine1). Identification based on phylogenetic analysis using 16S ribosomal DNA sequences showed that the two bacteria have a very close relationship with Rhodococcus qingshengii, R. baikonurensis and R. erythropolis. Based on the analyses using pairwise nucleotide alignment, the nucleotide sequences of strain 100A and 100D more similar to R. qingshengii, therefore, these bacteria were named Rhodococcus aff. qingshengii 100A and Rhodococcus aff. qingshengii 100D."

"ABSTRAKSuatu pemodelan matematis untuk mempelajari mekanisme kinetika sintesis biodiesel rute non alkohol menggunakan biokatalis pada berbagai kondisi operasi tertentu dikembangkan dalam penelitian ini. Mekanisme pemodelan sintesis biodiesel sederhana berbasis Michaelis - Menten dengan pertimbangan faktor adsorpsi digunakan, mengingat adanya perbedaan konsentrasi mula - mula maupun konsentrasi pada bulk, baik terhadap enzim, substrat, maupun produk. Validitas model ini diuji dengan melakukan fitting terhadap data yang diperoleh melalui percobaan pada berbagai kondisi tertentu dalam rangka mencari parameter-parameter kinetika. Persamaan model secara simultan diolah secara numeris menggunakan metode Runge-Kutta, dimana hasil fitting terbaik dari nilai parameter ditentukan menggunakan metode Simplex. Melalui penelitian ini, didapatkan bahwa model yang digunakan untuk sintesis biodiesel berbasis Michaelis - Menten dapat memberikan hasil fitting dan gambaran yang cukup baik mengenai pengaruh dari konsentrasi mula-mula enzim dan trigliserida yang digunakan, terhadap konsentrasi biodiesel yang dihasilkan pada suatu kondisi tertentu selama sintesis berlangsung.

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ABSTRACTA mathematical model describing biodiesel synthesis of non alcohol route using biocatalyst under various operating conditions was constructed in this research. The simplified kinetic mechanism based on Michaelis ' Menten with adsorption factor was considered in addition to the differences in the interfacial and bulk concentration of the enzyme, substrate and product. This modeling validation was doing by fitting the model equations with the experimental result data in order to obtain the kinetic parameters. A set of arbitrary values for the constants was assuming, and then the simultaneous differential equations based on Michaelis-Menten were numerically solved using Runge'Kutta method, where the best fitted values of the constants were determined using Simplex method. The results of simulation model for the synthesis of biodiesel using biocatalyst based on Michaelis ' Menten mechanism gave better fitted result and well described the effect of the initial enzyme concentration, initial concentrations of triglyceride and biodiesel on the entire process of biodiesel synthesis."

"Biodiesel (fatty acid methyl ester) telah diproduksi secara komersial melalui reaksi transesterifikasi minyak nabati dengan metanol menggunakan katalis alkali. Tetapi katalis alkali ini mempunyai beberapa kelemahan, seperti terjadinya reaksi pembentukan sabun, katalis yang bercampur homogen, dan proses pemurnian produk inilah yang menyebabkan harga biodiesel menjadi cukup mahal. Untuk mengatasi hal tersebut dikembangkan sintesis biodiesel menggunakan enzim lipase sebagai biokatalis. Biokatalis ini merupakan katalis heterogen, sehingga pemisahannya dari produk setelah reaksi berakhir dapat dilakukan dengan mudah. Namun, lipase terdeaktivasi oleh alkohol. Oleh karena itu, perlu dikembangkan metode baru untuk meningkatkan aktivitas dan stabilitas lipase dalam proses sintesis biodiesel. Metode baru yang akan dikembangkan adalah dengan cara mengganti alkohol dengan alkil asetat yang sama-sama berfungsi sebagai pensuplai alkil. Pada skripsi ini, penulis akan meneliti konsentrasi biodiesel (mol/L) yang terbentuk dari reaktan alkil asetat menggunakan biokatalis Candida rugosa dalam bentuk tersuspensi, lipase terimmobilisasi metode adsorpsi, dan lipase terimmobilisasi dalam bentuk sol-gel (Novozym 435). Menyelidiki pengaruh biokatalis terhadap konsentrasi biodiesel yang dihasilkan. Untuk lipase yang terimmobilisasi akan di uji stabilitasnya. Reaksi dilakukan dalam reaktor batch dan analisa sampel menggunakan HPLC. Berikutnya adalah melakukan pemodelan secara sederhana terhadap laju konsentrasi biodiesel yang terbentuk untuk menentukan nilai Km dan Vmax reaksi menggunakan persamaan Michaelis-Menten. Hasil penelitian menunjukan bahwa konsentrasi biodiesel terbesar yang dihasilkan adalah 15.02 (mol/L) mengunakan biokatalis Novozym 435. Namun untuk % yield biodiesel terbesar adalah 86.55 % yang dihasilkan menggunakan biokatalis dalam bentuk tersuspensi dengan rasio mol minyak : metil asetetat adalah 1:12. Konsentrasi biokatalis terbesar yang digunakan yaitu 4 (% wt) terbukti menghasilkan konsentrasi biodiesel yang terbesar pula. Untuk uji stabilitas lipase terimmobilisasi, dilihat dari % yield biodiesel terbentuk setelah 3 kali penggunaan reaksi, maka immobilisasi metode adsorpsi mempunyai stabilitas yang lebih baik dibandingkan dengan immobilisasi metode sol-gel (Novozym 435), dengan nilai % yield biodiesel terbentuk adalah 17.79% untuk metode adsorpsi dan 11.82 % untuk Novozym 435. Hasil penelitian kemudian dimodelkan menggunakan metode linierisasi Michaelis-Menten dengan nilai Vmax terbesar yaitu 0.0784 dan nilai Km terbentuk yaitu 12.975 yang didapat dari hasil sintesis biodiesel menggunakan lipase terimmobilisasi pada sol-gel (Novozym 435).

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The current biodiesel production processed commercially through transesterification of vegetabel oil with methanol using alkaline catalysts. Although conventional chemical technology using alkaline catalysts has been applied to biodiesel fuel production, there are several drawbacks to this approach, including saponification reaction occurs, the need for removal of catalyst, and.difficulties of this purity process at the end makes biodiesel price become expensive. The utilization of lipase in biodiesel production is considered as an effective means of circumventing these problems. However, effective methanolysis reactions using lipase have been developed, excess methanol would lead to inactivation of lipase and the lipase stability was poor. Hence, that's needed a new method to enhance the activity and stability of the lipase significantly.

In this paper, a new method is developed by replacing alcohol reaction route to non-alcohol reaction route. Methanol as acyl acceptor would be substituted by methyl acetate for biodiesel production. In this paper, biodiesel concentration (mol/L) that formed with alkyl acetate using different biocatalyst, Candida rugosa lipase in suspension form, immmobilized lipase with adsorpsi method, and immobilized lipase on acrylic resin (Novozym 435), will be observed. Then, the effect of biocatalyt to biodiesel cocentration (mol/L) formed will be studied too. Moreover, the stablitity of immobilized lipase will be tested. This eksperimental do in batch reactor and sample analyzed by HPLC. Additionally, result of this research will be modeled with Michealis-Menten mechanism through linierization method to find Vmax and Km value.

The result of this research shows that the highest biodiesel concentration is 15.02 (mol/L) which's obtained from Novozym 435 as biocatalyst. However, the highest % yield biodiesel formed is 86.55 % achieved from lipase in suspension form as biocatalyst with molar rasio oil to methyl acetat is 1:12. The highest biocatalyts concentrarion which used in this research is 4 (%wt) resulting the highest biodiesel concentration formed. For stability test toward immobilized lipase which have number of cycles 3 times for reaction, analyzed through % yield biodiesel resulted, shows that immobilized lipase with adsorption method have better stability than Novozym 435, which % yield biodiesel resulted is 17.79% for immobilized lipase with adsorption method and 11.82 % for Novozym 435. Then, result of this research is modeled by michaelis-menten mechanism with the highest value of Vmax = 0.0784 dan Km = 12.975 whih's obtained from Novozym 435 as biocatalyst."