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ALCHEMY Jurnal Penelitian Kimia
Published by Universitas Sebelas Maret
ISSN : 14124092     EISSN : 24434183     DOI : -
Core Subject : Science, Social, Engineering,
Chemical Engineering, Chemistry & Bioengineering Chemistry Energy Environmental Science Materials Science & Nanotechnology
ALCHEMY Jurnal Penelitian Kimia is a chemistry journal published by Sebelas Maret University, Surakarta. ALCHEMY Jurnal Penelitian Kimia publishes original research articles or review articles in organic chemistry, inorganic chemistry, analytical chemistry, physical chemistry, biochemistry, and environmental chemistry.
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Search results for , issue "Vol 17, No 2 (2021): September" : 10 Documents clear
Pengaruh Penggantian Kation-A/Sr oleh Ba pada Morfologi Partikel BaxSr(1-x)TiO3 (x = 0; 0,2; 0,4; 0,6; 0,8) Hasil Sintesis dengan Metode Lelehan Garam Hasal Maulidianingtiyas; Aldi Dwi Prasetiyo; Fikri Haikal; Indra Nur Cahyo; Vina Nurul Istighfarini; Anton Prasetyo
ALCHEMY Jurnal Penelitian Kimia Vol 17, No 2 (2021): September
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.17.2.48554.211-218

Abstract

SrTiO3 adalah material berstruktur perovskit yang dilaporkan berpotensi sebagai material fotokatalis. Penggantian pada sebagian kation-A material fotokatalis berstruktur perovskit dilaporkan dapat menurunkan energi celah pitanya, akan tetapi unsur pengganti juga dilaporkan mempengaruhi morfologi partikel yang terbentuk. Dalam penelitian ini, dikaji pengaruh penggantian kation-A pada SrTiO3(BaxSr(1-x)TiO3 (x = 0; 0,2; 0,4; 0,6; 0,8)) terhadap morfologi partikelnya. Senyawa uji disintesis dengan metode lelehan garam dan dalam penelitian ini menggunakan garam NaCl. Difraktogram sampel menunjukkan bahwa senyawa uji berhasil disintesis kecuali pada x = 0,8 masih ditemukan senyawa pengotor yang berupa TiO2 dan BaCO3. Gambar SEM menunjukkan bahwa keberadaan kation Ba mengubah morfologi partikel dari nearly cubic menjadi bentuk polihedra dan menyebabkanukuran partikel menjadi lebih besar.The Effect of Cation-A/Sr Replacement by Ba on Particle Morphology of BaxSr(1-x)TiO3 (x = 0; 0.2; 0.4; 0.6; 0.8) Synthesized by Molten Salt Method. SrTiO3 is a perovskite structure material that is reported as a potential photocatalyst material. Replacement of a part of the A-cation on a perovskite structure was reported can reduce its bandgap energy. However, the replacement element was also reported to affect the particle morphology. In this study, the effect of A-cation replacement on SrTiO3 (BaxSr(1-x)TiO3 (x = 0, 0.2, 0.4, 0.6, 0.8) to its particle morphology was studied. The sample of BaxSr(1-x)TiO3 (x = 0, 0.2, 0.4, 0.6) were synthesized by molten salt synthesis method (using NaCl salt). The diffractogram showed that the target compound was successfully synthesized but at x = 0.8 still found impurities TiO2 and BaCO3. SEM images showed that Ba-cation presence changes the particle morphology from nearly cubic to polyhedral shape and the particle size also becomes larger. 
A New Limonoid from the Seeds of Chisocheton lasiocarpus (Meliaceae) Ronauli Fitriana; Nurlelasari Nurlelasari; Darwati Darwati; Desi Harneti; Rani Maharani; Tri Mayanti; Unang Supratman
ALCHEMY Jurnal Penelitian Kimia Vol 17, No 2 (2021): September
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.17.2.44782.219-226

Abstract

 A New Limonoid from the Seeds of Chisocheton lasiocarpus (Meliaceae). Chisocheton is one of Meliaceae genus, which has about 53 species spreading in subtropical and tropical regions. One of the species is Chisocheton lasiocarpus. Chisocheton is rich in limonoids that have various biological activities such as anticancer, antimalarial, anti-inflammatory, antifeedant, antiviral, neuroprotective, and antimicrobial properties. This study aims to isolate limonoids from the seeds of C. lasiocarpus, and determine the structures. The dry powder of seeds of C. lasiocarpus (203.75 g) was macerated with subsequent n-hexane, ethyl acetate, and methanol. Extract of ethyl acetate was separated and purified using chromatography methods until a new limonoid, lasiocarpines (1) and one known limonoid, 14β,15β-epoxynimonol (2) were obtained. The purification process was guided by Ehrlich reagent. The chemical structures were identified by UV, IR, 1H-NMR, 13C-NMR, 2D NMR, and mass spectrometry.
Pengaruh Bentonit terhadap Pembentukan Fasa Polimorf dan Sifat Termal Membran Hibrida Poliviniliden Fluorida/Bentonit Edi Pramono; Rosid Eka Mustofa; Ozi Adi Saputra; Yulianto Adi Nugroho; Deana Wahyunigrum; Cynthia Linaya Radiman; Sayekti Wahyuningsih; Teguh Endah Saraswati; Sentot Budi Rahardjo; Witri Wahyu Lestari; Dian Maruto Widjonarko; Ari Handono Ramelan
ALCHEMY Jurnal Penelitian Kimia Vol 17, No 2 (2021): September
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.17.2.46136.177-184

Abstract

Kajian struktur dan degradasi termal pada membran hibrida poliviniliden fluorida (PVDF)/lempung bentonit (BNT) telah dilakukan. Penelitian ini bertujuan mengetahui pengaruh penambahan BNT terhadap pembentukan fasa PVDF dan sifat termalnya. Membran hibrida PVDF/lempung BNT dibuat dengan metode inversi fasa. Membran yang dihasilkan dikarakterisasi dengan attenuated total reflectance fourier transform infrared (ATR-FTIR), x-ray diffraction (XRD), dan differential scanning calorimetry (DSC). Hasil penelitian menunjukkan membran PVDF/BNT memiliki struktur polimorf PVDF fasa α dan β yang terkonfirmasi dari data FTIR dan XRD. Data DSC menunjukkan penurunan nilai titik leleh (Tm) dengan penambahan BNT, dan dengan rentang suhu pelelehan yang lebih kecil. Kristalisasi PVDF terjadi secara isothermal dan adanya BNT menghasilkan titik kristalisasi (Tc) pada suhu yang lebih tinggi dibandingkan membran PVDF murni. Analisis termal dengan DSC memberikan informasi komprehensif pelelehan dan kristalisasi dari polimorf PVDF pada matriks membran.Effect of Bentonite toward Polymorph Phase Formation and Thermal Properties of Polyvinylidene Fluoride/Bentonite Hybrid Membranes. The study of the structure and thermal properties of PVDF/bentonite (BNT) hybrid membranes has been carried out. This study aims to determine the effect of BNT addition on the phase formation and thermal properties of the PVDF. In this study, PVDF/BNT hybrid membranes were prepared through the phase inversion method. The resulting membrane was characterized by Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR), x-ray diffraction (XRD), and differential scanning calorimetry (DSC). The results showed that the PVDF/BNT membrane has a PVDF polymorph structure with α and β phases confirmed by FTIR and XRD data. The DSC data showed that the addition of BNT decrease of the melting point (Tm) and with a smaller melting temperature range. PVDF polymorph crystallization occurs isothermally and the presence of BNT produces a crystallization point (Tc) at a higher temperature than pristine PVDF membrane. Thermal analysis with DSC provides comprehensive information on melting and crystallization of PVDF polymorphs in the membrane matrix.
Sintesis, Karakterisasi dan Kinerja Membran Hidrofobik Menggunakan Polyvinyl Pyrrolidone (PVP) sebagai Aditif Umi Fathanah; Mirna Rahmah Lubis; Zuhra Mahyuddin; Syawaliah Muchtar; Mukramah Yusuf; Cut Meurah Rosnelly; Sri Mulyati; Rina Hazliani; Devi Rahmanda; Suraiya Kamaruzzaman; Meuthia Busthan
ALCHEMY Jurnal Penelitian Kimia Vol 17, No 2 (2021): September
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.17.2.48435.140-150

Abstract

Artikel ini melaporkan tentang sintesis, karakterisasi dan kinerja membran polyethersulfone (PES) yang dimodifikasi dengan aditif polyvinyl pyrrolidone (PVP) dengan tujuan untuk meningkatkan kinerja dan sifat antifouling membran. Membran PES modifikasi dibuat dengan penambahan 0,5% PVP sebagai aditif, menggunakan pelarut dimethyl sulfoxide (DMSO) dan n-methyl pyrrolidone (NMP). Pengaruh penambahan aditif dalam sistem membran dievaluasi dengan menganalisa perubahan struktur kimia menggunakan fourier transform infrared (FTIR), perubahan morfologi permukaan menggunakan scanning electron microscopy (SEM), uji kuat tarik menggunakan tensile strength meter, uji porositas membran dengan menggunakan metode gravimetri, serta pengujian kinerja filtrasi, dan sifat antifouling. Hasil analisa struktur membran dengan SEM menunjukkan adanya pengaruh jenis pelarut dan penambahan aditif terhadap perubahan morfologi membran. Selain itu modifikasi membran juga meningkatkan porositas, kinerja fluks permeasi serta sifat antifouling membran. Hasil uji filtrasi membran menunjukkan perolehan permeabilitas air pada membran D-0,5 dan N-0,5 masing masing sebesar 47,5 L/m2.jam.atm dan 41,5 L/m2.jam.atm dengan sifat antifouling membran modifikasi lebih besar dibandingkan dengan membran tanpa modifikasi. Synthesis, Characterization, and Performance of Hydrophobic Membranes Using Polyvinyl Pyrrolidone (PVP) as Additives. This paper discusses the synthesis, characterization and performance of polyethersulfone (PES) membranes modified with polyvinyl pyrrolidone (PVP) additives in order to improve the performance and antifouling properties of membranes. The modified PES membrane was prepared by adding 0.5% PVP as an additive, using dimethyl sulfoxide (DMSO) and n-methyl pyrrolidone (NMP) as solvents. The effect of adding additives to the membrane system was evaluated by analyzing changes in chemical structure using fourier transform infrared (FTIR), changes in surface morphology using scanning electron microscopy (SEM), tensile strength test using tensile strength meter, membrane porosity test using the gravimetric method, as well as testing the filtration performance and antifoulingproperties. The results of membrane structure analysis by SEM showed the influence of the type of solvent and additives on changes in membrane morphology. In addition, membrane modification also increases porosity, permeation flux performance, and membrane antifouling properties. The results of the membrane filtration test showed that the water permeability of D-0.5 and N-0.5 membranes was 47.5 L/m2.h.atm and 41.5 L/m2.h.atm, respectively, with modified membrane antifouling properties larger than the membrane without modification.
Analisis Logam Cr(III) Hasil Reduksi Cr(VI) dengan Teknik Voltammetri Lucutan Menggunakan Elektroda Pasta Karbon Termodifikasi EDTA: Studi Pendahuluan Annisa Anggitami; Dian Ayu Setyorini; Muhammad Yudhistira Azis; Ria Sri Rahayu
ALCHEMY Jurnal Penelitian Kimia Vol 17, No 2 (2021): September
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.17.2.47875.185-191

Abstract

Pada penelitian ini dikembangkan suatu metode pengukuran Cr(III) menggunakan elektroda pasta karbon (EPK) yang termodifikasi EDTA yang dapat diaplikasikan dalam penentuan efektivitas reduksi limbah Cr(VI) serta penentuan Cr(VI) dalam suatu sampel secara tidak langsung. Metode analisis voltammetri yang dilakukan menggunakan teknik voltammetri siklik, differential pulse voltammetry dan square wave voltammetry. EDTA merupakan ligan polidentat yang dapat mengkelat beberapa logam. Untuk logam kromium, EDTA hanya bisa mengkelat Cr(III). Oleh karena itu, dalam proses pengukurannya dilakukan reduksi Cr(VI) menjadi Cr(III) yang kemudian dapat dianalisis menggunakan EPK yang termodifikasi EDTA. Teknik voltammetri dipilih karena memiliki sensitivitas yang tinggi, limit deteksi yang rendah, dan memiliki daerah linier yang lebar. Hasil penelitian memperoleh bahwa Cr(III) dapat dianalisis dengan EPK termodifikasi EDTA menggunakan teknik voltammetri lucutan. Kondisi optimum pengukuran yang diperoleh adalah menggunakan elektroda dengan komposisi grafit: EDTA 25% berat (w/w), larutan elektrolit NaCl 0,1 M, waktu deposisi 5 detik, dan potensial deposisi 300 mV. Carbon Paste Electrode Modified by EDTA for Determination of Cr(III) Reduced from Cr(VI) by Using Stripping Voltammetry Method: A Preliminary Study. This study presented a method of measuring Cr(III) using carbon paste electrodes (CPE) modified by EDTA, which could be applied in determining Cr(VI) waste indirectly. EDTA is a polydentate ligand that can chelate several metals. For chromium metal, EDTA can only chelate Cr(III). Therefore, a reduction of Cr(VI) to Cr(III) was carried out in the measurement process and then analyzed using an EDTA-modified carbon paste electrode. The technique was chosen because it has a high sensitivity, low detection limit, and has a wide linear area. The results showed that Cr(III) could be analyzed using EDTA-modified CPE using stripping voltammetry. The optimum measurement conditions obtained were using an electrode with a composition of 25% weight (w/w) EDTA, 0.1 M NaCl as supporting electrolyte, 5 seconds for deposition time, and 300 mV for deposition potential.
Biodegradasi Pewarna Tekstil Rhodamin B oleh Bakteri Pembentuk Biofilm Sitti Wirdhana Ahmad; Nur Arfa Yanti; Fatimah Alwi Albakar
ALCHEMY Jurnal Penelitian Kimia Vol 17, No 2 (2021): September
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.17.2.49010.151-158

Abstract

Rhodamin B merupakan salah satu pewarna yang paling sering digunakan pada industri tekstil. Limbah pewarna tekstil ini dapat mencemari lingkungan jika masuk ke lingkungan melebihi ambang batas normal. Penggunaan bakteri pembentuk biofilm sebagai agensia pendegradasi Rhodamin B sangat memungkinkan karena mampu meningkatkan degradasi senyawa melalui interaksi antar bakteri sehingga mampu melengkapi proses metabolik. Tujuan penelitian ini adalah untuk mengetahui kemampuan isolat bakteri lokal pembentuk biofilm dalam mendegradasi pewarna tekstil Rhodamin B. Penelitian ini menggunakan 3 isolat bakteri pembentuk biofilm yang diperoleh dari perairan Tanjung Tiram, Kabupaten Konawe Selatan, Sulawesi Tenggara, yaitu isolat bakteri Chromohalobactersp. BfTT2.1.5, Bacillussp. BfTT2.11 dan Vibriosp. BfTT2.14. Kemampuan biodegradasi Rhodamin B oleh isolat bakteri pembentuk biofilm dideteksi menggunakan tiga parameter yaitu dekolorisasi pewarna Rhodamin B menggunakan metode spektrofotometri, kadar CO2 terlarut menggunakan metode titrasi dan total sel bakteri menggunakan metode drop plate. Berdasarkan uji kemampuan dalam mendegradasi pewarna tekstil Rhodamin B, Chromohalobacter sp. BfTT2.1.5 mampu mendegradasi Rhodamin B sebanyak 36,1% lebih tinggi dibanding Bacillus sp. BfTT2.11 (33,24%) dan Vibriosp. BfTT2.14 (16,18%). Ketiga isolat bakteri pembentuk biofilm mampu menggunakan Rhodamin B sebagai sumber karbon untuk pertumbuhannya. Oleh karena itu, isolat bakteri pembentuk biofilm sangat berpotensi digunakan sebagai agensia bioremediasi pewarna tekstil Rhodamin B.Biodegradation of Textile Dye Rhodamine B Using Biofilm-forming Bacteria. Rhodamine B is one of the most widely used dyes in the textile industry. This textile dye waste can pollute the environment if it enters the environment beyond the normal threshold. The use of biofilm-forming bacteria as agents to degrade Rhodamine B is possible because it can increase the degradation of compounds through interactions between bacteria to complete the metabolic process. The purpose of this study was to find out the resistance of local biofilm-forming bacteria isolates to Rhodamine B textile dyes and to find out the ability of local biofilm-forming bacterial isolates in degrading Rhodamine B textile dyes. This study used three isolates of biofilm-producing bacteria obtained from the waters of Tanjung Tiram, Konawe Selatan Regency, Southeast Sulawesi, namely Chromohalobactersp. BfTT2.1.5, Bacillussp. BfTT2.11 dan Vibriosp. BfTT2.14 bacterial isolates. The ability of biofilm-forming bacteria isolates to degrade Rhodamine B was detected using three parameters including decolorization of Rhodamine B dye using a spectrophotometry method, dissolved CO2 levels using the titration method, and total bacterial cells using the drop plate method. The results show that the isolate bacteria Chromohalobacter sp. BfTT2.1.5 is able to degrade Rhodamine B as much as 36.1% higher than Bacillus sp. BfTT2.11 (33.24%) and Vibriosp. BfTT2.14 (16.18%). The three biofilm-forming bacteria isolates were able to use Rhodamine B as a carbon source for growth. Therefore, the local isolates biofilm-forming bacteria are potential to be used as bioremediation agents for Rhodamine B textile dyes.
Senyawa Steroid dari Cocor Bebek (Kalanchoe tomentosa) sebagai Antibakteri Pseudomonas aeruginosa Risyandi Anwar; Lilis Siti Aisyah; Faridia Puspita Lestari; Delia Ilfani; Yenny Febriani Yun; Pebrian Diki Prestya
ALCHEMY Jurnal Penelitian Kimia Vol 17, No 2 (2021): September
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.17.2.51285.202-210

Abstract

Plak adalah pembentukan komunitas bakteri yang terorganisir pada permukaan gigi yang berupa lapisan tipis tidak berwarna. Pseudomonas aeruginosa adalah salah satu bakteri yang sangat berperan pada pembentukan plak. Metabolit sekunder yang terkandung dalam tanaman Kalanchoe tomentosa dapat digunakan sebagai antibakteri. Tahapan penelitian diawali dengan maserasi menggunakan pelarut n-heksan dan diklorometana. Ekstrak diklorometana dipisahkan menggunakan Kromatografi Cair Vakum (KCV) dengan n-heksana dan etil asetat sebagai pelarut bergradien selanjutnya direkristalisasi dengan n-heksan, hasil rekristalisasi didapatkan isolat 1. Isolat 1 dikarakterisasi dengan spektroskopi infra-red (IR), ultraviolet (UV) dan nuclear magnetic resonance hydrogen (1H NMR) serta dibandingkan dengan literatur. Isolat 1 diketahui merupakan stigmast-5-en-3ꞵ-ol atau ꞵ-sitosterol. Pada ekstrak diklorometana dan senyawa ꞵ-sitosterol kemudian ditentukan aktivitas antibakteri secara mikrodilusi didapatkan hasil bahwa ekstrak diklorometana dan senyawa ꞵ-sitosterol bukan hanya menunjukan sifat bakteriostatik tetapi juga bakterisid kuat terhadap bakteri Pseudomonas aeruginosadengan nilai Konsentrasi Hambat Minimum (KHM) <100 µg/mL.Steroid Compounds from Cocor Bebek (Kalanchoe tomentosa) as Antibacterial Pseudomonas aeruginosa. Plaque is a thin, colorless layer that adheres tightly to the surface of the teeth and contains a collection of bacteria. One of the bacteria that can form dental plaque is Porphyromonas aeruginosa. Kalanchoe tomentosa contain secondary metabolite which can be used as antibacterial. Stages of the study begin with maceration using n-hexane and dichloromethane. Dichloromethane extract was separated using Vacuum Liquid Chromatography (KCV) using n-hexane and ethyl acetate solvents and then recrystallized with n-hexane, the recrystallization results were obtained by isolate 1. Isolate 1 was marked by IR spectroscopy, and 1HNMR and compared with literature. Isolate 1 is known as stigmast-5-en-3ꞵ-ol or ꞵ-sitosterol. In dichloromethane extracts and ꞵ-sitosterol is determined by microdilution by microdilution. The results showed that dichloromethane extract and ꞵ-sitosterol compound not only showed strong bacteriostatic but also bacterisid activity against P. aeruginosa with Minimum Inhibiroty Concentration (MIC) <100 μg / mL.
Produksi Bioetanol sebagai Energi Terbarukan dari Rumput Laut Ulva reticulata Asal Pulau Timor Sefrinus Maria Dolfi Kolo; Jefry Presson; Pricilia Amfotis
ALCHEMY Jurnal Penelitian Kimia Vol 17, No 2 (2021): September
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.17.2.45476.159-167

Abstract

Rumput laut dengan kandungan karbohidrat dan lipid yang tinggi dianggap menjadi sumber energi terbarukan generasi ketiga. Penelitian ini bertujuan menentukan kadar gula pereduksi optimum, mengetahui tekstur permukaan serbuk sebelum dan sesudah hidrolisis serta menentukan kadar etanol hasil fermentasi. Kandungan karbohidrat rumput laut Ulva reticulata dapat dikonversi menjadi gula heksosa dan pentosa (glukosa, arabinosa, ramnosa, dan xilosa) melalui hidrolisis asam. Campuran gula optimum hasil proses hidrolisis kemudian dikonversi menjadi etanol menggunakan ragi Saccharomyces cerevisiae. Fermentasi dilakukan dengan konsentrasi inokulum 10% (v/v) selama 5 hari pada temperatur 30 °C dan pH 4,5. Analisis tekstur permukaan sampel dilakukan dengan Scanning Electron Microscopy (SEM). Analisis gula pereduksi dilakukan dengan metode DNS (Dinitro salisilat). Analisis etanol dilakukan dengan uji kualitatif dan kuantitatif menggunakan metode berat jenis dan kromatografi gas. Hasil penelitian menunjukkan bahwa kadar gula pereduksi meningkat seiring meningkatnya suhu hidrolisis pada suhu      75 °C ke 150 °C (2,3 – 23,7 g/L) dan mengalami penurunan kadar pada suhu 175 °C menjadi 17,1 g/L. Hasil analisis dengan variasi konsentrasi terhadap waktu 30, 40, 50, dan 60 menit terlihat bahwa kadar gula pereduksi meningkat seiring meningkatnya waktu hidrolisis dari 30 menit sampai 50 menit yakni 23,7 – 33,4 g/L dan mengalami penurunan pada waktu 60 menit yakni 19,2 g/L. Kadar gula pereduksi optimum sebesar 33,4 g/L  pada suhu 150 °C dengan konsentrasi asam 2 % pada waktu hidrolisis 50 menit. Tekstur permukaan serbuk sebelum dan sesudah hidrolisis mengalami perubahan yang signifikan. Hasil uji kualitatif etanol hasil fermentasi dibuktikan dengan adanya perubahan warna dari jingga menjadi biru. Hasil uji kadar etanol dengan metode berat jenis yakni sebesar 1% dan metode kromatografi gas sebesar 5,02%. Bioethanol Production as Renewable Energy from Ulva Reticulata Seaweed from Timor Island. Seaweed with carbohydrate and lipid content is considered to be the third generation of renewable energy sources. The carbohydrate content of Ulva reticulata seaweed can be converted into hexose and pentose sugars (glucose, arabinose, ramnose, and xylose) through acid hydrolysis. The optimum sugar mixture resulting from the hydrolysis process is then converted to ethanol using Saccharomyces cerevisiae yeast. Fermentation was carried out with an inoculum concentration of 10% (v/v) for five days at a temperature of 30 °C and a pH of 4.5. Analysis of the surface texture of the sample was carried out by Scanning Electron Microscopy (SEM). Reducing sugar analysis was performed using the DNS (Dinitrosalicylate) method. Ethanol analysis was carried out by qualitative and quantitative tests using specific gravity and gas chromatography methods. The results showed that the reducing sugar content increased with increasing hydrolysis temperature at 75 °C to 150 °C (2.3 – 23.7 g/L) and decreased levels at 175 °C to 17.1 g/L. The results of the analysis with various concentrations of 30, 40, 50, and 60 minutes showed that reducing sugar levels increased with increasing hydrolysis time from 30 minutes to 50 minutes, namely 23.7 – 33.4 g/L and decreased at 60 minutes, namely 19.2 g/L. The optimum reducing sugar content was 33.4 g/L at 150 °C with an acid concentration of 2% at 50 minutes of hydrolysis. Powder surface texture before and after hydrolysis experienced significant changes. The qualitative test results of fermented ethanol are evidenced by a change in color from orange to blue. The results of the ethanol content test using the specific gravity method were 1%, and that using the gas chromatography method was 5.02%.
Characterization of Methyl Ester Sulfonate (MES) from Mahagony (Swietenia macrophylla King) with Variations in H2SO4 Concentration and Sulfonation Duration Laily Nurliana; La Ode Kadidae; Sunarti Sunarti; Rustam Musta
ALCHEMY Jurnal Penelitian Kimia Vol 17, No 2 (2021): September
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.17.2.51613.192-201

Abstract

Methyl ester sulfonate derived from mahogany (Swietenia macrophylla K.) oil has been characterized. The research began by synthesizing mahogany methyl ester (ME) in 4 stages: pressing, degumming, esterification, and transesterification. The next process was synthesizing methyl ester sulfonate (MES) also in four stages: sulfonation, bleaching, neutralization, and drying. The reactant for MES synthesis in this study was H2SO4 with a mole ratio of 1:6 and variations in the concentration of H2SO4 (70%, 75%, 80%, 85%, and 90%) as well as variations in the duration of sulfonation (45, 60, 75, 70, and 105 minutes) to determine the characteristics of the synthesized MES including density, acid number, and emulsion stability. The effect of the combination of treatment variations was analyzed using the two-way ANOVA test and the least significant difference (LSD) test. This research showed that MES from mahogany seed oil from a combination of variations in treatment has a density ranging from 0.91 to 0.97 g/mL where the LSD test at α = 0.05 produces three different MES density groups due to variations in the concentration of H2SO4 namely A (70 % and 75%), B (80% and 85%), and C (90%). The resulting MES acid numbers ranged from 4.69 ‒ 17.74 mgKOH/g sample with three different groups of MES acid numbers due to variations in the concentration of H2SO4, namely A (85 and 90%), B (75% and 80%), and C (70%). The stability of mahogany oil-based MES emulsion ranged from 0.000 ‒ 0.975 and two different MES emulsion stability groups were obtained due to variations in the concentration of H2SO4, namely A (80% and 85%) and B (70%, 75%, and 90%). FTIR spectrophotometer showed the presence of S=O groups at wavenumber 1172 cm-1 and S‒O groups at wavenumbers 972.12 cm-1 and 879.54 cm-1 proved that MES was successfully synthesized.
Identifikasi Aktivitas Inhibitor Enzim Tirosinase Senyawa Turunan Flavonoid pada Kulit Buah Cokelat (Theobroma cacao L) secara In Silico Sani Ega Priani; Taufik Muhammad Fakih
ALCHEMY Jurnal Penelitian Kimia Vol 17, No 2 (2021): September
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.17.2.45317.168-176

Abstract

Limbah kulit buah cokelat diketahui mengandung berbagai senyawa aktif, termasuk di antaranya adalah golongan flavonoid. Senyawa flavonoid diketahui berpotensi memiliki aktivitas inhibitor enzim tirosinase, suatu enzim yang menstimulasi proses pembentukan melanin. Penelitian ini bertujuan untuk mengevaluasi interaksi antara senyawa flavonoid dari kulit buah cokelat dengan enzim tirosinase menggunakan metode penambatan molekuler secara in silico. Pengujian dilakukan dengan beberapa tahapan yakni preparasi makromolekul enzim, pemodelan molekul senyawa uji, identifikasi sisi aktif molekul enzim, identifikasi dan evaluasi penambatan molekuler, serta simulasi dinamika molekuler senyawa uji dengan molekul enzim. Hasil simulasi penambatan molekuler antara molekul enzim dengan ligan alaminya yakni tirosin memberikan energi ikatan sebesar -4,91 kkal/mol. Senyawa flavonoid dari kulit buah cokelat yakni apigenin, epikatekin, katekin, kaemferol, kuersetin, dan kuersitrin  diketahui memiliki afinitas pada sisi aktif enzim tirosinase dengan energi ikatan berturut turut -6,14; -6,17; -6,01; -5,89; -6,13; -6,81 kkal/mol. Hasil simulasi dinamika molekuler menunjukkan kuersitrin memiliki stabilitas yang baik dengan nilai RMSD rata-rata dan nilai energi bebas ikatan MM/PBSA masing-masing sebesar ±1,73 Å dan -80,12 kJ/mol. Hasil penelitian menunjukkan bahwa senyawa turunan flavonoid tersebut mampu berikatan dengan sisi aktif enzim tirosinase dengan afinitas yang lebih baik dibandingkan dengan ligan alaminya diamati dari nilai energi ikatannya. Senyawa turunan flavonoid yang terkandung dalam kulit buah cokelat berpotensi menjadi inhibitor kompetitif dari enzim tirosinase.Identification of In Silico Tyrosinase Inhibitory Activity of Flavonoid Derivative Compounds in Cocoa Pod Husk (Theobroma cacao L.). Cocoa pod husk was known to contain several active compounds, such as flavonoids. Flavonoid compounds are known to potentially have inhibitory activity of the tyrosinase, the enzyme which stimulates melanin synthesis.This study was conducted to evaluate the molecular interaction between flavonoids from cocoa pod husk with tyrosinase enzyme using in silico molecular docking method. The study was carried out through several stages, including preparation of enzyme macromolecules, modeling the molecule of the test compound, identifying the active site of the enzyme molecule, identifying and evaluating molecular docking, and molecular dynamics simulations of the test compound with the enzyme molecule. Molecular docking simulation between the enzyme and its natural ligand (tyrosine) produces binding energy of -4.91 kcal/mol. Flavonoid compounds from cocoa pod husk, including apigenin, epicatechin, catechin, kaempferol, quercetin, dan quercitrin, have an affinity on the active site of the enzyme with binding energy were -6.14; -6.17; -6.01; -5.89; -6.13; -6.81 kcal/mol, respectively. Then the molecular dynamics simulation shows quercitrin has good stability interaction with the average RMSD value and the MM/PBSA binding-free energy values of ±1.73 Å and -80.12 kJ/mol, respectively. The results showed that flavonoids of cocoa pod husc extract have an affinity to the active site of the enzyme, with a stronger binding energy than the original ligand. The flavonoid compounds of cocoa pod husk potential as a competitive inhibitor of the tyrosinase enzyme.

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