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Abstrak :
ABSTRAK
Dimetil eter (DME) adalah salah satu bahan bakar alternatif terbarukan yang dapat menggantikan pemakaian energi fosil di Indonesia. Penggunaan senyawa ini menghasilkan pembakaran yang efisien serta ramah lingkungan. Akan tetapi, dimetil eter diketahui menyebabkan degradasi pada material karet, yang banyak digunakan sebagai sealant ataupun selang pada tempat penyimpanan bahan bakar dari mesin pembakaran. Hingga penelitian ini, setiap jenis material karet mengalami degradasi yang berbeda-beda sehubungan dengan senyawa ini. Oleh karena itu, penelitian ini utamanya ditujukan untuk menentukan jenis degradasi material karet, khususnya karet alam vulkanisat, terhadap dimetil eter. Selain itu, penelitian ini hendak melihat pengaruh komposisi filler dan petroleum oil dari karet alam vulkanisat terhadap degradasi tersebut. Eksperimen yang dilaksanakan mencakup: sintesis, uji degradasi, karakterisasi mekanis dan morfologi. Nilai komposisi filler yang dipakai untuk sintesis yaitu: 10, 30, dan 60 phr; sedangkan nilai komposisi petroleum oil yang dipakai adalah 0, 10, dan 20 phr. Uji degradasi karet alam vulkanisat dilakukan dengan merendam seluruh sampel dalam pressure vessel yang berisi dimetil eter cair, yang diperoleh dari proses pencairan fasa gasnya. Karakterisasi mekanis yang dilakukan mencakup: % perubahan massa, kekuatan tensile, elongasi maksimum, dan kekerasan. Karakterisasi morofologinya berupa pengamatan langsung dan scanning electron microscopy (SEM). Data-data karakterisasi tersebut menunjukkan bahwa karet alam vulkanisat mengalami degradasi jenis absorpsi dan ekstraksi oleh karena dimetil eter. Adapun penambahan komposisi filler ditemukan dapat mengurangi pengaruh degradasi, sedangkan penambahan komposisi petroleum oil justru memperparah degradasi. Namun demikian, petroleum oil juga dibutuhkan karena dapat membuat distribusi filler merata pada seluruh bagian karet alam vulkanisat. Maka dari itu, dengan meninjau keseluruhan data tersebut, didapatkan bahwa komposisi filler dan petroleum oil yang memberikan perlindungan paling optimal terhadap degradasi oleh dimetil eter masing-masing bernilai 30 phr dan 10 phr.

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ABSTRACT
Dimethyl ether (DME) is one of the renewable energy that could replace the usage of fossil fuel in Indonesia. The usage of this compound could produce efficient and environmental-friendly combustion. However, based on previous research, dimethyl ether is found to cause degradation on rubber-based materials, which are used as sealant or hose inside the fuel tanker of combustion engines. Until this research, it is found that each types of rubber has suffered different kinds of degradation that caused by dimethyl ether. Therefore, the main goal of this research is to determine what kind of degradation will happen on rubber, especially vulcanized natural rubber, that cause by dimethyl ether. Moreover, this research is going to see the effect of filler and petroleum oil composition contained in vulcanized natural rubber against that degradation. There are three parts of experiments will conducted: synthesis, degradation testing, mechanical and morphology characterization. The variation value of filler composition used are 10, 30, and 60 phr; while the variation value of petroleum oil composition are 0, 10, and 20 phr. Degradation testing is done by immersing all samples inside pressure vessel that have been filled with liquid dimethyl ether, which produced from its gas by liquefaction process. Mechanical characterization that observed includes: % change of mass, tensile strength, maximum elongation, and hardness. On the other side, morphology characterization is done by direct observation and scanning electron microscopy (SEM). Those datas reveals that vulcanized natural rubber suffer absorption and extraction, two types of degradation, because of dimethyl ether. Increasing of filler composition could reduce the impact of degradation, while increasing of petroleum oil composition will give the opposite results. However, it is also found that petroleum still must needed to make distribution of filler goes through all parts of rubber. Therefore, based on these datas, we get that 30 phr of filler and 10 phr of petroleum pil will give the optimal protection on vulcanized natural rubber against degradation caused by dimethyl ether.

Abstrak :
ABSTRAK
Asam galat merupakan senyawa yang dikenal memiliki potensi terapetik yang luas, sebagai antibakteri, antifungal, antiviral, antinflamasi, antialergi, hepatoprotektif, antitrombotik, dan antikarsinogenik. Potensi asam galat sebagai antibakteri merupakan peluang untuk menemukan alternatif antibakteri baru. Reaksi esterifikasi dengan senyawa alkohol dilakukan pada asam galat untuk menghasilkan derivat alkil ester galat. Senyawa asam galat dan derivatnya diujikan pada Pseudomonas aeruginosa. Kontrol positif penelitian ini adalah antibiotik Seftazidim. Pengujian dilakukan dengan metode makrodilusi berdasarkan observasi kekeruhan tabung dan uji konfirmasi dengan plat agar darah. Senyawa dibagi dalam lima kelompok konsentrasi berbeda dan dilakukan pengukuran dua kali pengulangan duplo . Hasil penelitian dinyatakan dalam Konsentrasi Hambat Minimum KHM berdasarkan hasil metode makrodilusi. Dari sepuluh derivat alkil ester galat yang diujikan, dua derivat yang memiliki aktivitas penghambatan terhadap pertumbuhan terhadap bakteri P.aeruginosa, yakni senyawa derivat benzil galat pada konsentrasi 1967 ?g/mL dan amil galat pada konsentrasi 1822 ?g/mL. Peningkatan aktivitas antimikroba terhadap P.aeruginosa dipengaruhi oleh jumlah gugus atom karbon C , jumlah cabang dan cincin aromatis benzene.

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ABSTRACT
Gallic acid is known as substance which has broad bioactivities as antibacterial, antifungal, antiviral, anti inflammatory, anti allergy, hepatoprotective, anti thrombotic, and anti cancer. Potent antibacterial activity of gallic acid has become an opportunity to develop a new antibacterial agent through structure modification of gallic acid. Antibactrial activity of gallic acid and its alkyl ester derivatives were evaluated against Pseudomonas aeruginosa with Seftazidim antibiotic as a positive control. Macrodilution method is used to observe the turbidity of each tested sample and followed by confirmation test by blood agar. The tested samples are divided into five different concentration. Antibacterial activity is expressed by Minimum Inhibitory Concentration MIC based on the result of macrodilution method. Among ten alkyl ester derivatives of gallic acid , two derivatives showed antibacterial activity against Pseudomonas aeruginosa, namely, benzyl gallate MIC 1967 g mL and amyl gallate MI C 1822 g mL . Improved antimicrobial activity against P.aeruginosa are influenced by the number of atoms of carbon C , amount of branch and aromatics benzene ring.

Abstrak :
Tetraeter lipid (TEL) merupakan salah satu produk hasil ekstraksi Thermoplasma acidophilum yang bersifat stabil dalam suhu tinggi dan pH rendah. TEL dapat ditambahkan dalam kombinasi liposom untuk menambah kestabilan liposom. Salah satu kombinasinya adalah liposom yang dibuat dari lesitin / fosfatidil kolin kuning telur (Egg yolk Phosphatidyl Choline / EPC) dan TEL 2,5 mol % dari Thermoplasma acidophilum yang kemudian dinamakan liposom EPC-TEL 2,5. Pada liposom EPC-TEL 2,5 belum pernah diuji apakah TEL dapat didegradasi oleh tubuh (hepar) secara in vivo, sehingga perlu dilakukan uji untuk menilai hasil degradasi TEL dalam suspensi hepar mencit. Penilaian hasil degradasi TEL oleh hepar dilakukan dengan membandingkan retention factor (Rf) pada hepar kontrol yang diberikan TEL secara in vitro dan hepar mencit 1 jam setelah injeksi liposom intraperitoneal pada lembar kromatografi lapis tipis (KLT). Pada hasil penelitian tampak bahwa, baik pada hepar kontrol dengan TEL maupun pada hepar 1 jam setelah injeksi liposom intraperitoneal tidak ditemukan bercak TEL pada lembar KLT. Oleh karena itu hasil penelitian ini belum dapat menyimpulkan ada atau tidaknya degradasi TEL di hepar, sehingga dibutuhkan penelitian lanjutan dengan menggunakan dosis TEL yang lebih tinggi, eluen yang tepat, lembar KLT yang lebih panjang, standar TEL dan metabolitnya, dan alat pendeteksi liposom yang lebih sensitif.

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Tetraether lipid (TEL) is one of the extraction product from Thermoplasma acidophilum which is stable at high temperature and low pH. TEL can be added in liposome combinations to increase liposome's stability. One of the combinations is liposome made from lecithin / Egg yolk Phosphatidyl Choline (EPC) and 2.5 mol % TEL from Thermoplasma acidophilum, named EPC-TEL 2.5 liposome. Whether TEL in EPC-TEL 2.5 liposome can be degraded by liver within the body in vivo hasn't been tested, therefore the test to measure TEL degradation in mouse's liver cells suspension is needed. The measurement of degradation product is conducted by comparing retention factors (Rf) of control liver with TEL added in vitro and liver taken 1 hour after intraperitoneal liposome injection on thin layer chromatography (TLC) sheet. The result shows, both for control liver with TEL added in vitro and liver taken 1 hour after intraperitoneal liposome injection, there are no TEL spots on TLC sheet. Thus, the result couldn't conclude TEL degradation in liver, hence further studies using higher TEL dosage, appropriate eluent, longer TLC sheet, standard for TEL and its metabolites, and device which could detects liposome more sensitive are needed.

Abstrak :
This study is to verify the usage of DME as an alternative fuel and its production routs. As it is clear the energy, its supply and consumption is a very important concern. Countries are developing and as a result of that the energy consumption is increasing. Growing energy consumption is directly related to the depletion of fossil fuels particularly petroleum based fuels. So the world has to think of using other fuels which have at least the same performance and its production is cost-effective. One of these fuels is Dimethyl ether (DME). DME is very promising fuel and research on its characteristics and efficiencies show that it can be considered as a future fuel as it is cheap, environmental friendly and has good efficiency. Another advantage of DME production is that it has different applications and is a versatile fuel. Furthermore, similarity of its physical properties to LPG makes DME handling, storing and transportation easy however DME has low viscosity and lubricity. These mentioned disadvantages which are solvable may cause problems if enough attention is not paid to them. Typically DME is produced from natural gas as a feedstock although coal and biomass are also other possible feedstock to be utilized. To produce DME, natural gas is first converted to synthesis gas via ATR method (Auto thermal reforming) and then is converted to DME through direct method. This research aimed to be done to investigate about the possibility of using DME as a future fuel by discussing about its characteristics, advantages and disadvantages. Moreover, its various production pathways has been talked about and tried to compare them in different aspects.

Abstrak :
Pada penelitian ini dilakukan sintesis senyawa ester gliserol oleat serta ester gliserol asam lemak hasil hidrolisis minyak jarak menggunakan enzim lipase Candida rugosa dalam pelarut n-heksana. Dilakukan pula optimasi reaksi melalui perbandingan mol asam lemak:gliserol, yaitu 1:1, 1:2, 1:3, dan 1:4. Persen konversi tertinggi diperoleh pada perbandingan mol asam lemak:gliserol 1:4 dengan nilai persen konversi 86,26 ester gliserol oleat dan 92,32 untuk ester gliserol asam lemak hasil hidrolisis minyak jarak. Produk esterifikasi dikarakterisasi menggunakan instrumen FTIR. Spektrum FTIR menunjukkan adanya gugus identik C=O ester pada bilangan gelombang 1748,25 cm-1 dan 1735,37 cm-1 berturut-turut untuk ester gliserol oleat dan ester gliserol asam lemak. Kedua ester kemudian diuji emulsifier dan antimikroba untuk membuktikan adanya sifat emulsifier dan aktivitas antimikroba. Hasil dari uji emulsifier menunjukkan bahwa tipe emulsi dari kedua jenis ester tersebut adalah air dalam minyak. Uji aktivitas antimikroba menunjukkan bahwa ester gliserol asam lemak hasil hidrolisis pada konsentrasi 80 w/w memiliki aktivitas inhibisi yang paling kuat terhadap Propionibacterium acne dan Staphylococcus epidermidis, sedangkan ester gliserol oleat tidak menunjukkan adanya aktivitas antimikroba terhadap kedua bakteri uji.

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In this study, synthesis of glycerol ester oleic and glycerol ester castor oil fatty acid using lipase Candida rugosa in n hexane solvent was carried out. Optimization reaction was also carried out through mol ratio variation of fatty acid glycerol, 1 1, 1 2, 1 3, and 1 4. The highest conversion percentage obtained at the mole ratio 1 4, which valued 86,26 for glycerol ester oleic and 92,32 for glycerol ester castor oil fatty acid. The esterification products were characterized by FTIR instrument. The FTIR spectrum showed the presence of identical group of C O ester at wave number 1748,25 cm 1 and 1735,37 cm 1 for glycerol ester oleic and glycerol ester castor oil fatty acid, respectively. Both esters were then examined by emulsifier and antimicrobial test to prove the ability of emulsifying and its antibacterial activity. The results of the emulsifier test turn that the emulsion type of both esters are oil in water. The antibacterial activity test indicate that ester glycerol castor oil fatty acid at 80 concentration w w performed strongest inhibition activity against propionibacterium acne and Staphylococcus epidermidis, while glycerol ester oleic had no activity against both bacteria.

Abstrak :
Sintesis senyawa ester gliserol laurat dan ester gliserol asam lemak hasil hidrolisis minyak kelapa dilakukan dengan reaksi esterifikasi menggunakan lipase Candida rugosa dan pelarut n-heksana. Optimasi reaksi dilakukan dengan menggunakan variasi perbandingan mol antara asam lemak dengan gliserol 1:1; 1:2; 1:3; dan 1:4 mol. Didapatkan persen konversi tertinggi 61 untuk ester gliserol laurat dan 55 untuk ester gliserol asam lemak hasil hidrolsis pada perbandingan mol 1: 4. Identifikasi produk menggunakan instrumen FT-IR Fourir Transform-Infra Red menunjukkan adanya puncak serapan C=O ester pada bilangan gelombang 1748 cm-1 untuk ester gliserol laurat maupun ester gliserol asam lemak hasil hidrolisis. Selanjutnya pada uji aktivitas sebagai emulsifier, kedua jenis ester memiliki aktivitas sebagai emulsifier dengan tipe emulsi air dalam minyak. Uji aktivitas antimikroba menunjukkan bahwa ester gliserol laurat membunyai aktivitas yang kuat untuk Propionibacterium acne dan Staphylococcus epidermidis pada konsentrasi 75. Sedangkan untuk ester gliserol asam lemak, menghasilkan aktivitas yang sedang pada konsentrasi 75 terhadap Propionibacterium acne dan pada konsentrasi yang sama menghasilkan aktivitas yang lemah terhadap Staphylococcus epidermidis.

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Synthesis of glycerol ester hydrolized coconut oil fatty acid and lauric acid was conducted enzymatically using Candida rugosa lipase in n hexane solvent. The optimization of the reaction was carried out by using a mole ratio variation between fatty acids and glycerol, 1 1 1 2 1 3 and 1 4 mole mole . The highest percent conversion percentage is 61 for glycerol ester of lauric acid and 55 for glycerol ester fatty acid of hydrolyzed coconut oil in 1 4 mole ratio. The product identification using FT IR Fourier Transform Infra Red instrument shows the absorption peak C O ester at wave number 1748 cm 1 for both glycerol ester of lauric acid and fatty acid hydrolyzed coconut oil. Furthermore, in the activity test as the emulsifier, both types of ester have activity as emulsifiers with water in oil emulsion type. Ester glycerol laurate against bacteria Propionibacterium acne and Staphylococcus epidermidis has strong activity at concentrations of 75 . For fatty acid glycerol esters of hydrolysis, medium category was produced on Proponibacterium acne at 75 concentration. And at the same concentration, resulting in weak antimicrobial activity against Staphylococcus epidermidis.

Abstrak :
Pada penelitian ini, dilakukan sintesis senyawa ester gliserol asam lemak hasil hidrolisis minyak sawit dan ester gliserol oleat secara enzimatik menggunakan lipase Candida rugosa EC. 3.1.1.3 dalam pelarut n-heksana. Optimasi reaksi dilakukan dengan membuat variasi perbandingan mol antara asam lemak dengan gliserol, yaitu 1:1, 1:2, 1:3, dan 1:4. Hasil persen konversi tertinggi diperoleh dari variasi perbandingan 1:4 sebesar 42 untuk ester gliserol asam lemak hidrolisis minyak sawit dan 58 untuk ester gliserol oleat. Hasil karakterisasi menggunakan FT-IR untuk ester gliserol asam lemak hidrolisis minyak sawit dan ester gliserol oleat menunjukkan adanya puncak serapan gugus C=O ester pada bilangan gelombang 1748 cm-1. Pada ester gliserol asam lemak hidrolisis minyak sawit dan ester gliserol oleat dilakukan uji emulsifier. Tipe emulsi yang terbentuk adalah minyak dalam air o/w . Uji aktivitas antimikroba ester gliserol asam lemak hasil hidrolisis minyak sawit maupun ester gliserol asam oleat ternyta tidak dapat menghambat pertumbuhan Staphylococcus epidermidis dan Propionibacterium acnes.

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Synthesis of glycerol palm oil fatty acid ester and glycerol oleic acid ester were conducted enzymatically using Candida rugosa lipase EC. 3.1.1.3 in n hexane solvent. Optimization of esterification reaction was carried out by varying the mole ratio of fatty acid to glycerol 1 1 1 2 1 3 1 4. The highest conversion percentage was obtained at mole ratio 1 4 with the value of 42 for glycerol palm oil fatty acid ester and 58 for glycerol oleic ester. Esterification products were characterized by FT IR. The FT IR spectrum showed the ester bond was formed as indicated at 1748 cm 1 for the absorption peak of C O ester group. Both esters were then examined by simple emulsion test and were proved to be an emulsifier. Based on the emulsion test, it was proved that the esterification products have properties as an emulsifier for oil in water o w emulsion type. The antimicrobial activity assay showed that glycerol palm oil fatty acid ester and and glycerol oleic acid ester cannot inhibit the growth of Staphylococcus epidermidis and Propionibacterium acnes.