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Indonesian Journal of Chemistry

ijc
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Published by Universitas Gadjah Mada

ISSN : 14119420 EISSN : 24601578 DOI : -

Core Subject : Science, Engineering,

Chemical Engineering, Chemistry & Bioengineering Chemistry

Indonesian Journal of Chemistry is an International, peer-reviewed, open access journal that publishes original research articles, review articles, as well as short communication in all areas of chemistry including applied chemistry. The journal is accredited by The Ministry of Research, Technology and Higher Education (RISTEKDIKTI) No : 21/E/KPT/2018 (in First Rank) and indexed in Scopus since 2012. Since 2018 (Volume 18), Indonesian Journal of Chemistry publish four issues (numbers) annually (February, May, August and November).

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Articles 1,956 Documents

111 112 113 114 115

Combination of Genetic Manipulation Improved Saccharomycopsis fibuligera α-Amylase Secretion by Pichia pastoris Shabarni Gaffar; Dessy Natalia; Toto Subroto; Oo Suprijana; Soetijoso Soemitro
Indonesian Journal of Chemistry Vol 19, No 2 (2019)
Publisher : Universitas Gadjah Mada

This study assessed the combinations of genetic manipulation; signal peptide modification, gene dosage increment and co-expression of folding component, to increase Saccharomycopsis fibuligera R64 α-amylase (Sfamy) secretion in Pichia pastoris. Sfamy native signal peptide was replaced with modified signal peptide which contained 15 amino acid of mouse salivary α-amylase signal peptide fused to the pro-region of the signal peptide of Saccharomyces cerevisiae α-mating factor (α-MF). Increase in gene dosage was identified by screening for P. pastoris harboring multicopies of the Sfamy gene. Whereas, co-expression of folding component was done by addition of Protein Disulfide Isomerase (PDI). Expression plasmids harboring Sfamy containing modified signal sequence (pPICZA-MS-Sfamy) was used to transform P. pastoris GS115, and gene dosage increment was screened using zeocin. Effect of PDI co-expression on secretion levels of Sfamy was assessed by constructing the pPIC3.5K-Pdi1 plasmid and introducing into P. pastoris harboring multicopies of MS-Sfamy for expression of Sfamy. Signal peptide modification consequently increased Sfamy secretion by P. pastoris by 3.3-fold compared to native signal peptide. Gene dosage increment had improved Sfamy secretion by 11-fold in P. pastoris [MS-Sfamy] resistant to 2000 μg/mL zeocin, compared to P. pastoris harboring one copy of WT-Sfamy. Hence, PDI co-expression increased the secretion of Sfamy by 2-fold as compared without PDI co-expression. In summary, the combination of genetic manipulation successfully increased Sfamy secretion by 20-fold compared to P. pastoris harboring one copy of WT-Sfamy.

Hydrocracking of Coconut Oil over Ni-Fe/HZSM-5 Catalyst to Produce Hydrocarbon Biofuel Muhammad Al-Muttaqii; Firman Kurniawansyah; Danawati Hari Prajitno; Achmad Roesyadi
Indonesian Journal of Chemistry Vol 19, No 2 (2019)
Publisher : Universitas Gadjah Mada

This present study was aimed to investigate the hydrocracking of coconut oil using Ni-Fe/HZSM-5 catalyst in a batch reactor at three reaction temperatures (350, 375, and 400 °C). The Ni-Fe/HZSM-5 catalyst was prepared by using incipient wetness impregnation. The Ni-Fe/HZSM-5 catalyst was characterized using XRD, BET, and SEM-EDX. From XRD results, the loading of Ni and Fe did not change the crystalline structure of HZSM-5 catalyst. The surface area of HZSM-5 was 425 m2/g and decreased after the addition of metals (Ni and Fe) into HZSM-5 support. These changes implied that Ni and Fe particles were successfully dispersed on the HZSM-5 surface and incorporated into HZSM-5 pore. The product of hydrocarbon biofuel was analyzed using GC-MS. The GC-MS results of hydrocarbon biofuel showed the highest compounds for n-paraffin and yield for gasoil was 39.24 and 18.4% at a temperature of 400 °C, respectively. The reaction temperature affected the yield and the composition of hydrocarbon biofuel. At this reaction temperature condition, decarboxylation and decarbonylation were favored; lead to the formation of n-alkanes with an odd number of carbon atoms chain length.

Biodegradation of Extractable Petroleum Hydrocarbons by Consortia Bacillus cereus and Pseudomonas putida in Petroleum Contaminated-Soil Abubakar Tuhuloula; Suprapto Suprapto; Ali Altway; Sri Rachmania Juliastuti
Indonesian Journal of Chemistry Vol 19, No 2 (2019)
Publisher : Universitas Gadjah Mada

Contamination of soil by the activities of exploration, production, and disposal of oil waste into the environment causes serious damage to the environmental ecosystem, the target of processing by the bacteria as a model for remediation of oil contaminated site. Thus, the study was focused on determining the biodegradation percentage of extractable petroleum hydrocarbons as a function of the oil concentration. This research was conducted in a slurry bioreactor with mixed contaminated soil to water ratio of 20:80 (wt.%). A consortium of Bacillus cereus and Pseudomonas putida bacteria 10% (v/v) and 15% (v/v) with the ratio of 2:3, 1:1, and 3:2 was inserted into the slurry bioreactor and a single reactor was used as a control. The result of identification with an initial concentration of extractable petroleum hydrocarbons of 299.53 ng/µL, after 49 days of incubation for bacterial consortium 10% (v/v), the concentration was reduced to 85.31; 32.43; 59.74; and 112.22 ng/µL respectively and the biodegradation percentage was 71.5; 89.17; 80.05; and 62.54%. As for the bacterial consortium concentration of 15% (v/v) with the same ratio and control, the effluent concentration was 12.48; 7.72; 18.93 ng/µL, respectively or the biodegradation percentage was 95.83; 97.42; 93.68%.

Synthesis of Mesoporous Carbon from Merbau Wood (Intsia spp.) by Microwave Method as Ni Catalyst Support for α-Cellulose Hydrocracking Andaru Dena Prasiwi; Wega Trisunaryanti; Triyono Triyono; Iip Izul Falah; Darma Santi; Muhammad Fajar Marsuki
Indonesian Journal of Chemistry Vol 19, No 3 (2019)
Publisher : Universitas Gadjah Mada

Synthesis of mesoporous carbon from Merbau wood (Intsia spp.) waste by microwave method as nickel catalyst support for α-cellulose hydrocracking had been carried out. The Merbau wood sawdust was carbonized at 800 °C to produce C800 and the C800 was treated by microwave irradiation (399 W) for 5 min to produce C800MW. The Merbau wood flakes, which were only treated by microwave irradiation (399 Watts) for 30 min produced CMW. Wet impregnation technique was carried out to disperse the Ni metal (1.0, 1.5, and 2.0 wt.%) onto the best mesoporous carbon. The mesoporous carbons were analyzed by Fourier Transform Infra-Red Spectroscopy (FTIR), Surface Area Analyzer (SAA) and Scanning Electron Microscopy (SEM). The hydrocracking of pyrolyzed α-cellulose was carried out at 400 °C. The liquid product was analyzed by Gas Chromatograph-Mass Spectrometer (GC-MS). The results showed that the C800MW was the best performance carbon and it had a specific surface area, total pore volume, average pore diameter and acidity of 364.12 m2/g, 0.28 cm3/g, 3.03 nm, and 2.18 mmol/g, respectively. The Ni1.5/C800MW catalyst produced the highest conversion of liquid product (58.76 wt.%) than the Ni1/C800MW (57.51 wt.%) and Ni2/C800MW (34.18 wt.%).

Antibacterial Properties of Biofilm Schiff Base Derived from Dialdehyde Cellulose and Chitosan Agung Pratama; Firman Sebayang; Rumondang Bulan Nasution
Indonesian Journal of Chemistry Vol 19, No 2 (2019)
Publisher : Universitas Gadjah Mada

Cellulose and chitosan are natural polymers that have been used as biocomposite. The aim of this research is to obtain biofilms from chitosan and oxidized cellulose crosslinks. This research is divided into three steps, i.e., isolation of cellulose from oil palm trunk and oxidation of cellulose using NaIO4 (0.2; 0.4; 0.6; 0.8; 1.0 mg/mL) to obtain dialdehyde cellulose (DAC), crosslink of oxidized cellulose with chitosan (DD = 72.85%) to obtain biofilm of chitosan/DAC (CDAC), and characterization of biofilms. The crosslinked reaction was confirmed by FT-IR analysis that showed the spectrum of Schiff base C=N group at 1651 cm–1. Tensile strength increased gradually when the NaIO4 concentration used was 0.2–0.6 mg/mL, but after those concentrations, the tensile strength slightly decreased. The morphology analysis showed that CDAC had smoother morphology than DAC, which was shown rough and showed some particle indicated the presence of unreacted cellulose. CDAC biofilms that prepared with 1.0 mg/mL NaIO4 showed the greatest antibacterial activity.

Conceptual Difficulties Experienced by First-Year Undergraduate Chemistry Students in Assigning Oxidation Number: A Case Study of High School Chemistry Textbooks Rahmat Basuki
Indonesian Journal of Chemistry Vol 20, No 1 (2020)
Publisher : Universitas Gadjah Mada

The purpose of this research was to investigate first-year undergraduate chemistry students’ understanding in assigning oxidation number following a case-study course instruction. A list of multiple choice question and interview section was formulated to identify the initial knowledge as representative of their conceptual understanding in assigning oxidation number obtained from their chemistry textbooks. This study revealed that most of 34 students who participated were confused about the nature of oxidation number. In the section of the interview which focused on applying “The Rules”, many students experienced more problems in assigning oxidation number of sulfur in S2O32– ion. Several misconceptions relating to the inappropriate assumption in assigning oxidation number were identified. The data illustrated how students attempt to make sense of the concept obtained from High School with the knowledge they had already constructed in solve of a given question. The research implied that the teachers, lecturers, curriculum developers, and High School Chemistry textbooks authors need to be cognizant of the importance of related concept (electronegativity and dot-Lewis structure) with oxidation number. The high school and chemistry textbook authors were recommended to introduce this interconnection (including formal charge) to minimize the misconception and conceptual difficulties experienced by first-year undergraduate chemistry students in assigning oxidation number.

Attenuated Total Reflectance-FTIR Spectra Combined with Multivariate Calibration and Discrimination Analysis for Analysis of Patchouli Oil Adulteration Zaki Fahmi; Mudasir Mudasir; Abdul Rohman
Indonesian Journal of Chemistry Vol 20, No 1 (2020)
Publisher : Universitas Gadjah Mada

The adulteration of high priced oils such as patchouli oil with lower price ones is motivated to gain the economical profits. The aim of this study was to use FTIR spectroscopy combined with chemometrics for the authentication of patchouli oil (PaO) in the mixtures with Castor Oil (CO) and Palm Oil (PO). The FTIR spectra of PaO and various vegetable oils were scanned at mid infrared region (4000–650 cm–1), and were subjected to principal component analysis (PCA). Quantitative analysis of PaO adulterated with CO and PO were carried out with multivariate calibration of Partial Least Square (PLS) regression. Based on PCA, PaO has the close similarity to CO and PO. From the optimization results, FTIR normal spectra in the combined wavenumbers of 1200–1000 and 3100–2900 cm–1 were chosen to quantify PaO in PO with coefficient of determination (R2) value of 0.9856 and root mean square error of calibration (RMSEC) of 4.57% in calibration model. In addition, R2 and root mean square error of prediction (RMSEP) values of 0.9984 and 1.79% were obtained during validation, respectively. The normal spectra in the wavenumbers region of 1200–1000 cm–1 were preferred to quantify PaO in CO with R2 value of 0.9816 and RMSEC of 6.89% in calibration, while in validation model, the R2 value of 0.9974 and RMSEP of 2.57% were obtained. Discriminant analysis was also successfully used for classification of PaO and PaO adulterated with PO and CO without misclassification observed. The combination of FTIR spectroscopy and chemometrics provided an appropriate model for authentication study of PaO adulterated with PO and CO.

Antibacterial Activity of Benzyl Benzoate and Crotepoxide from Kaempferia rotunda L. Rhizome Hartiwi Diastuti; Mochammad Chasani; Suwandri Suwandri
Indonesian Journal of Chemistry Vol 20, No 1 (2020)
Publisher : Universitas Gadjah Mada

Benzyl benzoate and crotepoxide are the major components of Kaempferia rotunda L. rhizome. However, the bioactivity study of benzyl benzoate and crotepoxide as the antibacterial activity were still limited. Therefore, the antibacterial activity of benzyl benzoate and crotepoxide against four pathogenic bacteria, i.e., Escherichia coli ATCC 25922, Enterococcus aerogenes ATCC 13048, Bacillus cereus ATCC 6538 and Staphylococcus aureus ATCC 11778 were investigated. The isolation steps were include the extraction by maceration with acetone, then the acetone extract was partitioned with n-hexane:methanol (1:1) and ethyl acetate:water (1:1) respectively. The isolation by liquid vacuum chromatography followed by column chromatography was obtained benzyl benzoate from the n-hexane fraction and crotepoxide from ethyl acetate fraction. The molecular structure of isolated compounds was identified based on NMR (1D and 2D) spectroscopic data. The antibacterial activity assay of isolated compounds was carried out using the disc diffusion method. The antibacterial evaluation confirms that the benzyl benzoate and crotepoxide exhibits a medium level activity. Benzyl benzoate showed highest antibacterial activity against B. cereus at the MIC of 50 μg/mL and inhibitory zone of 5.9 mm, while the crotepoxide showed highest antibacterial activity against E. aerogenes at the MIC of 100 μg/mL with inhibitory zone 6.1 mm.

Synthesis of Graphite Porous Electrode Based on Coconut Shell as a Potential Cathode in Bioelectrosyntesis Cell Aris Mukimin; Rustiana Yuliasni; Nur Zen; Kukuh Wicaksono; Januar Arif Fatkhurahman; Hanny Vistanty; Rizal Awaludin Malik
Indonesian Journal of Chemistry Vol 19, No 2 (2019)
Publisher : Universitas Gadjah Mada

Electrodes, as well as microorganisms, are key materials for the development of bioelectrosynthesis cell reactor. Materials used as electrodes should be inert, crystalline in structure with high surface area and porous morphology, enhancing their electroactive and adsorptive properties. Carbon material derived from coconut shell was modified by simultaneous sintering-activation methods, FeCl3 and ZnCl2 were supplemented at temperature 900 °C at the non-atmospheric condition. The modified carbon was then molded with polyvinyl alcohol as a binder and the temperature was maintained at 80 °C and 10 ton of pressure. Molded carbon was then installed in bioelectrosynthesis cell with a working volume of 200 mL, as a cathode. XRD, BET, and SEM measurements showed the transformation of carbon surface from amorphous into the crystalline, increased surface area (11 times higher) and higher porosity (up to 500 nm). This cathode modification was able to increase current density up to 4 times and reduce CO2 into butyrate, 250 mg/L, in bioelectrosynthesis cell.

Adsorption and Photodegradation of Cationic and Anionic Dyes by TiO2-Chitosan Nanocomposite Imelda Fajriati; Mudasir Mudasir; Endang Tri Wahyuni
Indonesian Journal of Chemistry Vol 19, No 2 (2019)
Publisher : Universitas Gadjah Mada

The adsorption and photodegradation of cationic and anionic dyes by TiO2-chitosan nanocomposites have been studied. This study investigated the specific surface area, pores volume, pores size of TiO2-Chitosan nanocomposite, and determination kinetics of the reaction on the adsorption and photodegradation process. The methods were carried out by mixing TiO2-nanocomposite into cationic and anionic dyes in various contact times and initial dye concentrations. The results showed that nanocomposite adsorption capacity increased with an increase in the amount of chitosan (TiO2/Chit 0.13) even though the specific surface area (SBET) was reduced. The results indicated that the adsorption on nanocomposite was influenced by the amount of -NH2 and -OH on the chitosan surface. The maximum adsorption capacity (qm) and the observed reaction constant (kObs) for MO were also known to be higher than MB, which means that the TiO2-chitosan nanocomposites could remove anionic dye more than cationic one.

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