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All Journal Reaktor TEKNIK METANA JURNAL TEKNOLOGI KIMIA DAN INDUSTRI Bulletin of Chemical Reaction Engineering & Catalysis Seminar Nasional Teknik Kimia Kejuangan Majalah Ilmiah MOMENTUM Indonesian Journal of Chemistry Jurnal Pasopati : Pengabdian Masyarakat dan Inovasi Pengembangan Teknologi International Journal of Renewable Energy Development Bulletin of Chemical Reaction Engineering & Catalysis JURNAL REKAYASA KIMIA & LINGKUNGAN
Bakti Jos
Departemen Teknik Kimia, Fakultas Teknik, Universitas Diponegoro, Kampus Undip Tembalang Jl. Prof. Soedarto, SH, Semarang, Indonesia 50275
Aerospace Engineering Automotive Engineering Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Computer Science & IT Control & Systems Engineering Earth & Planetary Sciences Education Electrical & Electronics Engineering Energy Engineering Environmental Science Industrial & Manufacturing Engineering Materials Science & Nanotechnology

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Sequential Microwave-Ultrasound Assisted Extraction of Flavonoid from Moringa oleifera: Product Characteristic, Antioxidant and Antibacterial Activity Aji Prasetyaningrum; Bakti Jos; Ratnawati Ratnawati; Nur Rokhati; Teguh Riyanto; Gian Restu Prinanda
Indonesian Journal of Chemistry Vol 22, No 2 (2022)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.65252

Abstract

Moringa oleifera leaves contain secondary metabolites in flavonoid compounds known to prevent several diseases. Therefore, appropriate extraction methods are required to produce extracts with a high yield of flavonoids from Moringa. In this study, the extraction from Moringa leaves was carried out using the sequential microwave/ultrasound-assisted extraction (MUAE) method compared with sequential ultrasound/microwave (UMAE), microwave (MAE), ultrasound (UAE), and maceration (ME). The effects of the time, temperature, and percentage of ethanol were studied on total flavonoid content using AlCl3 colorimetric assay. The extracts were analyzed by Scanning Electron Microscopy (SEM), Fourier Transforms Infrared Spectrophotometry (FTIR), and High-Performance Liquid Chromatography (HPLC). The antioxidant and antibacterial activities were tested using DPPH-scavenging and disc diffusion methods. The results of SEM surface analysis on various extraction methods show differences on each surface. The FTIR spectrum showed the presence of flavonoid O–H at 3200 cm–1, C=O at 1621 cm–1, and C–O at 1019 cm–1. In the results of HPLC, MUAE extracts 16.70 mg/ 100 g flavonoid quercetin at the retention time of 4.5 min, with the highest total flavonoids (2.89 mg QE/g), the highest antioxidant activity (IC50 72.31 µg/mL), and highest antibacterial activity (S. aureus 7 mm, E. coli 2 mm).
Copper and Lead Ions Removal by Electrocoagulation: Process Performance and Implications for Energy Consumption Aji Prasetyaningrum; Dessy Ariyanti; Widayat Widayat; Bakti Jos
International Journal of Renewable Energy Development Vol 10, No 3 (2021): August 2021
Publisher : Center of Biomass & Renewable Energy, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/ijred.2021.31665

Abstract

Electroplating wastewater contains high amount of heavy metals that can cause serious problems to humans and the environment. Therefore, it is necessary to remove heavy metals from electroplating wastewater. The aim of this research was to examine the electrocoagulation (EC) process for removing the copper (Cu) and lead (Pb) ions from wastewater using aluminum electrodes. It also analyzes the removal efficiency and energy requirement rate of the EC method for heavy metals removal from wastewater. Regarding this matter, the operational parameters of the EC process were varied, including time (20−40 min), current density (40−80 A/m2), pH (3−11), and initial concentration of heavy metals. The concentration of heavy metals ions was analyzed using the atomic absorption spectroscopy (AAS) method. The results showed that the concentration of lead and copper ions decreased with the increase in EC time. The current density was observed as a notable parameter. High current density has an effect on increasing energy consumption. On the other hand, the performance of the electrocoagulation process decreased at low pH. The higher initial concentration of heavy metals resulted in higher removal efficiency than the lower concentration. The removal efficiency of copper and lead ions was 89.88% and 98.76%, respectively, at 40 min with electrocoagulation treatment of 80 A/m2 current density and pH 9. At this condition, the specific amounts of dissolved electrodes were 0.2201 kg/m3, and the energy consumption was 21.6 kWh/m3. The kinetic study showed that the removal of the ions follows the first-order model.
UV Irradiation and Ozone Treatment of κ-Carrageenan: Kinetics and Products Characteristics Aji Prasetyaningrum; Widayat Widayat; Bakti Jos; Yudhy Dharmawan; Ratnawati Ratnawati
Bulletin of Chemical Reaction Engineering & Catalysis 2020: BCREC Volume 15 Issue 2 Year 2020 (August 2020)
Publisher : Masyarakat Katalis Indonesia - Indonesian Catalyst Society (MKICS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.9767/bcrec.15.2.7047.319-330

Abstract

The low molecular weight (LMW) of sulfated polysaccharides including k-carrageenan, is shows a wide spectrum of biological activities. This research investigates the influence of UV irradiation, ozone (O3), and the combination of O3/UV methods on the depolymerization of k-carrageenan. The depolymerization kinetics of k-carrageenan using the Advanced Oxidation Process (UV/O3) was also studied. Furthermore, the intrinsic viscosity method was used to determine the average molecular weight of the research sample, and a mathematical model was developed to predict the kinetic rate constant, as a function of ozone dosage and UV irradiation intensity. Therefore, the physicochemical and morphological properties of the degraded k-carrageenan were analyzed by FT-IR, SEM, and XRD. The intrinsic viscosity k-carrageenan decreases with increasing UV light intensity and ozone concentration. The combination of UV/O3 treatment appeared to be more effective than the individual approaches, as the highest kinetic rate constant for depolymerization was 1.924×10-4 min-1, using 125 mg/L ozone concentration and 40 mW/cm2 of UV lamp intensity. This research also evaluated the relationship between various experimental conditions, including UV lamp power dissipation and ozone concentration on the reaction kinetics model, and the results suggest that lower effect is contributed by UV irradiation intensity. In addition, FT-IR spectra showed the absence of any significant change in the functional properties of k-carrageenan treated with UV and O3 processes, although the morphological properties of the LMW k-carrageenan were rougher and more porous than the native k-carrageenan. Copyright © 2020 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 
Kinetics of the Enzymatic Hydrolysis of Sweet Cassava Starch and Bitter Cassava Flour and Gadung (Dioscorea hispida Dennst) Flour at Low Temperature Hargono Hargono; Bakti Jos; Andri Cahyo Kumoro
Bulletin of Chemical Reaction Engineering & Catalysis 2017: BCREC Volume 12 Issue 2 Year 2017 (August 2017)
Publisher : Masyarakat Katalis Indonesia - Indonesian Catalyst Society (MKICS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.9767/bcrec.12.2.808.256-262

Abstract

Starch is a potential substrate for this purpose, but the extra cost is needed to hydrolyze it into reducing sugar. As an alternative to the expensive and energy demanding conventional hydrolysis process, the low-temperature hydrolysis is being studied. Granular Starch Hydrolysing Enzyme (GSHE) was used in the process to degrade starch into reducing sugar at 30°C and pH 4. The substrates included bitter cassava flour, sweet cassava starch, and gadung flour. Starch concentrations studied were 50, 100, 150, 200, 250, 300, 350, and 400 g/L, respectively, while concentration of enzyme was 1.5 % (w/w). The optimum condition of the process was hydrolysis using 200 g/L of substrate concentration and enzyme  concentration of 1.5% for 12 h. It was found that the reducing sugar was  49.3  g/L and the productivity of reducing sugar (Qrs) was 4.11 (gL-1 h-1).   Lineweaver-Burk plot of Michaelis-Menten equation was used to study the inhibition kinetics. The Michaelis-Menten constants (Km)  for these three substrates were determined as 141.64 g/L, 137,64 g/L and 140.84 g/L for bitter cassava flour, sweet cassava starch, and gadung flour, respectively. The value of  Vm/Km, which denotes the affinity of the enzyme to the substrate, were determined and compared, and the result showed that the affinity (Vm) to the enzyme to this substrate followed  the order of sweet cassava starch˃ bitter cassava flour˃ gadung flour, and all are non-competitive inhibitor, while the  Ki value was 0.022 h -1. 
Inhibition Effect of Ca2+ Ions on Sucrose Hydrolysis Using Invertase Hargono Hargono; Bakti Jos; Abdullah Abdullah; Teguh Riyanto
Bulletin of Chemical Reaction Engineering & Catalysis 2019: BCREC Volume 14 Issue 3 Year 2019 (December 2019)
Publisher : Masyarakat Katalis Indonesia - Indonesian Catalyst Society (MKICS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.9767/bcrec.14.3.4437.646-653

Abstract

Fermentable sugar for bioethanol production can be produced from molasses due to its high sucrose content but Ca2+ ions found in the molasses may affect the hydrolysis. Therefore, this paper was focused to study the effect of Ca2+ ions as CaO on sucrose hydrolysis using invertase and to obtain the kinetic parameters. The kinetic parameters (KM and Vmax) were obtained using a Lineweaver-Burk plot. The value of KM and Vmax parameters were 36.181 g/L and 21.322 g/L.h, respectively. The Ca2+ ions act as competitive inhibitor in sucrose hydrolysis using invertase. Therefore, the inhibition mechanism was followed the competitive inhibition mechanism. The value of inhibition constant was 0.833 g/g. These parameters were obtained from the non-substrate inhibition process because this study used the low substrate concentrations which means the fermentable sugar production was low. Hence, there were still more challenges to studying the simultaneous effect of substrate and Ca2+ on sucrose hydrolysis to produce high fermentable sugar. 
Analisis Penambahan Ion Na dan Ca pada Hidrolisis Pati Singkong (Manihot esculanta) untuk Meningkatkan Aktivitas Enzim: Studi Kinetika Hidrolisis Hargono, Hargono; Jos, Bakti; Satriadi, Hantoro; Zakaria, Muhammad Fahmi
TEKNIK Vol. 43, No. 1 (2022): May 2022
Publisher : Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/teknik.v43i1.41985

Abstract

Sweet cassava is tuber that contains large amount of starch so that it can produce reducing sugars. The addition of metal ions can increase enzyme activity. The purpose was to study the addition of Na and Ca ions on reducing sugars concentration and to study the hydrolysis kinetics. Experiments were carried out at various concentrations of substrates (100, 200, and 300 g/L), enzyme concentrations (1 and 1.5% (w/w)), addition of Na and Ca ions of 60 ppm. The hydrolysis method was conducted at temperature of 30°C with the enzyme StargenTM 002 at pH 4, for 24 hours. The results showed that starch concentrations of 100-200 g/L were able to significantly increase the reducing sugars at enzyme concentration of 1.5% (w/w). The addition of Ca ions increased the concentration of reducing sugar by 64% while the addition of Na ions increased it by 18.9%. The best reducing sugar concentration (68.79 g/L) was obtained at starch concentration of 200 g/L and enzyme concentration of 1.5% (w/w) with the of Ca ions. Kinetic studies show that phenomenon follows Michaelis-Menten equation with Vmax valued of 6.053; 8,881; 15.106 g/L.hour, respectively. So that, addition of Na and Ca ion can increase the enzyme activity
Adsorption Photocatalytic Removal of Rhodamine B using Dodecyl Dimethyl Betaine (BS12) Intercalated Silver Tetratungstate-Bentonite composites: Effect of Ag and Surfactant Loading, pH, and its Subsequent Economic Feasibility Sumardiono, Siswo; Setiawan, Fajar Kasih; Jos, Bakti; Cahyono, Heri
Reaktor Volume 25 No.1 April 2025
Publisher : Department of Chemical Engineering, Faculty of Engineering, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/reaktor.25.1.%p

Abstract

The potential of silver tetratungstate-doped bentonite intercalated with zwitterionic surfactant for removing Rhodamine B (RhB) was evaluated by comparing three composites, namely, AB (acid-activated bentonite), AB impregnated with Ag8W4O16 photocatalyst (Ag@AB), and Ag@AB intercalated with dodecyl dimethyl betaine (BS12) surfactant (Ag@OAB) with respect to their photocatalytic adsorption performance. The AB composite was prepared by treating natural bentonite with hydrochloric acid (HCl). Next, Ag@AB was synthesized by wet impregnation of Ag₈W₄O₁₆ onto AB. Lastly, the Ag@OAB was formed by intercalating the BS12 surfactant onto the Ag@AB composite. The morphology of the composite structures was characterized using Scanning Electron Microscopy (SEM). The addition of 4% Ag (w/w) tetratungstate W4O16 and 50% CEC BS12 to AB produced RhB removal percentages of 66% and 59%, respectively, compared to 65% for AB. The maximum removal percentage was achieved at pH 4 for the AB, Ag@AB, and Ag@OAB composites with RhB removal percentages of 67%, 71%, and 44%, respectively. The AB composite showed the highest regenerative ability compared to Ag@AB and Ag@OAB, with AB maintaining RhB removal at 70% after five regeneration cycles, while Ag@AB and Ag@OAB only reached four and three regeneration cycles. The total production cost of AB is fourteen to sixteen times lower than that of Ag@AB and Ag@OAB composites. In summary, the impregnation of the Ag₈W₄O₁₆ photocatalyst onto AB, resulting in the Ag@AB composite, increases the RhB removal efficiency compared to pristine AB. In contrast, the intercalation of the BS12 surfactant in Ag@OAB composite led to a decrease in RhB removal efficiency, resulting in the lowest performance among the three composites.
Effect of Coagulants in Curd forming in Cheese Making Wardhani, Dyah Hesti; Jos, Bakti; Abdullah, Abdullah; Suherman, Suherman; Cahyono, Heri
Jurnal Rekayasa Kimia & Lingkungan Vol 13, No 2 (2018): Jurnal Rekayasa Kimia & Lingkungan (December, 2018)
Publisher : Chemical Engineering Department, Syiah Kuala University, Banda Aceh, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23955/rkl.v13i2.12157

Abstract

Cheese is one of the popular dairy products with high nutrient content. Coagulation as an important process in making cheese, wherein, the curd will be separated from the milk whey. This coagulation can use the enzyme rennet, acid, or a combination of both. This study aims to study the effect of coagulant agents on yield, protease enzyme activity, and curd texture on cheese making. Coagulant agents used are acetic acid, citric acid, lime and lemon combined with the enzyme rennet. The process begins with pasteurized milk and analyzed, the milk is pasteurized and analyzed first to obtain moisture content, density and pH. The coagulant added is 25-45% with a base of 50 ml of milk and 5 mL of the enzyme rennet. The curd formed is then separated from the whey using a filter cloth and analyzed for its water content and pH. The coagulant of acetic acid and citric acid produced a higher yield curd of 94.66% (4% acetic acid) and 93.9% (5% citric acid) compared to the highest yield of curd that can be produced by lime and lemon coagulant which is 68 72% (lemon orange 45%) and 61.84% (lime 45%). The texture of the curd formed by lime and lemon juice is more fragile than the curd texture with coagulant of acetic acid and citric acid. Each coagulant provides a diverse response to protease enzyme activity.
Co-Authors . Widayat A Abdullah Aat Zaki Mubarok Abdullah Abdullah Abdullah Abdullah Aji Prasetyaningrum Al Farrel A. Raemas Andri Cahyo Kumoro Angga Mei Sarah Aprianto Aprianto Bambang Pramudono Dessy Ariyanti Dessy Ariyanti Diah Susetyo Retnowati Dyah Hesti Wardhani Fadlillah Fani Feninda Nevrita Fitri Lafifa Gian Restu Prinanda Hantoro Satriadi Hargono Hargono Hargono Hargono Hargono Hargono Hargono Hargono Hargono Hargono Hargono Hargono Heri Cahyono Heri Cahyono Heru Susanto Isti Pudjiastuti Jonathan Ginting Listiyana Riska Muchlis Riki Darmawan Noer Abyor Handayani Nur Rokhati Patrick Andreas Praditya Nugraha Prayudi Eko Setyawan Prayudi Eko Setyawan Ratnawati Ratnawati Sadam Arrois Salsabila, Unik Hanifah Satrio Kuntolaksono Setiawan, Fajar Kasih Siswo Sumardiono Suherman Suherman Suherman, Suherman Sukaryo Sukaryo Teguh Riyanto Widayat Widayat Y Yufidani Yanuar Ariyanto Yudha Satria Yudha Satria Yudhy Dharmawan Zakaria, Muhammad Fahmi