Engineering Headway Vol. 14

Abstract: It is important for consumers to be aware of the source of gelatin due to religious restrictions, as pork is forbidden for consumption by Muslims and Jews, and cows are forbidden for consumption by Hindus. Fishery waste, such as fish bones and scales, can be a promising alternative raw material for gelatin production, as they are halal for consumption. The process of gelatin preparation involves several stages, including pretreatment, degreasing, demineralization, and hydrolysis using bromelain enzyme. hydrolysis process using bromelain enzyme ranging from 1, 2, 3, 4, 5, 6 and 7% at 300 rpm and temperature 55 °C. Hydrolysis was carried out for 6 hours and 9 hours for each concentration. Characterizations of gelatin was conducted for pH, water content, ash content, Fourier Transform-Infrared Analyzer (FTIR), X-ray Fluorescence (XRF) Spectrometry and Gas chromatography (GC). Based on the research, the optimum conditions for produce halal gelatin from red snapper scales was obtained at 5% bromelain enzyme for 9 hours for hydrolized collagen to gelatin with a yield of 11.414%, pH of 5.3, water content of 7%, ash content of 2.1%, and free from alcohol and heavy metals. The FTIR spectra show that the absorption at wavenumber 2944.5, 1628.74, 1524.55, and 1332.14 cm^-1 respectively, indicating the presence of C–H, C=O, C=C and C–N stretching. The presence of absorption peaks of that functional groups show gelatin has been formed. XRF analysis show the absence of heavy metals as Hg, Pb, Cd, and Zn. Fish-based gelatin in this study is produced through a halal process, using halal ingredients, and its product does not contain alcohol, thus the gelatin produced in this study is a halal product.

Abstract: Bioconversion of water hyacinth (Eichhornia crassipes) cellulose into glucose was successfully conducted by Trichoderma viride. Cellulose was isolated from water hyacinth by delignification. The delignification method is carried out for bond breaking of lignin, hemicellulose and cellulose. The Fourier Transform Infrared (FTIR) spectra of the delignification products confirmed that cellulose was successfully isolated. FTIR spectra showed the presence of peaks for the C=O and C=C groups, the C-H and C─O groups of polysaccharide bonds, and the C─O─C vibrational peak of pyranose ring. Cellulose was obtained in 58.84% yield. Cellulose was then converted into glucose through enzymatic processes by Trichoderma viride. Initially, these fungi are required to be adapted and rejuvenated with cellulose media. Gradual adaptation and rejuvenation aims to optimize the performance of fungi in converting cellulose into glucose. Cultures were incubated at 35°C and 120 rpm in an orbital shaker incubator. The FTIR spectra of glucose showed the presence of peaks for-OH alcohol and C=O bonds of glucose typical absorption peaks. Thus, the glucose conversion was successful. Water hyacinth can be a sustainable cellulose source for glucose synthesis in tropical and subtropical countries. Furthermore, water hyacinth has other advantages, such as its high breeding rate, availability, and low cost. Keywords: Eichhornia crassipes, glucose, water hyacinth, Trichoderma viridee

Abstract: This review study thoroughly examines recent developments in graphene materials derived from bioresources, following their development from successful laboratory experiments to commercial applications. Bioresources, which include various organic materials such as biomass and agricultural waste, have become a viable starting point for graphene manufacturing. This article emphasizes the benefits of biological resources and new developments in hydrothermal and chemical reduction as laboratory-scale synthesis processes. This review stands out because it includes a bibliometric analysis that provides quantitative insight into the state of the field. This paper includes successful case studies where laboratory breakthroughs have opened the door to large-scale implementation before moving to industrial-scale production. It also covers issues such as cost effectiveness and process improvements that arise as scale increases. This study assesses the financial feasibility of incorporating these materials into the graphene market while highlighting the environmentally friendly benefits of using the bioresource. The analysis concludes with perspectives on potential future research avenues, including improvements in biological resource selection and innovative applications. This is an invaluable resource for academics, professionals, and policymakers seeking continued progress in graphene technology.

Abstract: This research investigates the utilization of Escherichia coli and Lapindo mud in a two-chamber Microbial Fuel Cells (MFCs) series. MFCs are tools that convert chemical energy into electrical energy with the help of catalytic reactions from microorganisms. This research uses a dual chamber reactor connected by a salt bridge, with graphite electrodes placed in each chamber and connected by copper cables. Lapindo mud contains heavy metals, such as Cu and Pb. In small amounts, heavy metals required for maintaining various biochemical and physiological functions in living organisms, but in greater amounts they can become hazardous or toxic. Heavy metals are major environmental contaminants. The toxicity of heavy metals is an important issue for ecological, evolutionary, nutritional, and environmental reasons. Lapinda mud was placed in the cathode chamber to produce electricity. The cathode chamber was packed using a mixture of Lapindo mud, ammonium chloride, and sulfuric acid. Various amount Lapindo mud was applied, such as 35, 45, and 55 g. On the anode side, E. coli bacteria was used as microorganisms under anaerobic conditions with glucose as a substrate. E. coli undergoes metabolism, producing NAD+ to transfer electrons to produce electricity. Electrical voltage measurements are carried out periodically every hour for 35 h. The best performance was achieved when 55 g of Lapindo mud was used. The exponential phase of E. coli growth occurred at 10 h of cultivation, resulting in a spike in electricity production of 228.13 mV. After reaching the stationary phase of bacterial growth, the electricity generation remained constant for 19-30 h, which reached 342.9 mV; 0.01 mA, 0.034167 watts.

Abstract: This study proposed to synthesize the silver nanoparticle/kappa carrageenan-chitosan (AgNPs/KCar-Chit) hydrogel films and identify the effects of AgNPs on their physical properties and antibacterial performance. The AgNPs/KCar-Chit has been synthesized in 2 stages. The first stage was the synthesis of AgNPs/KCar colloids via the chemical reduction route assisted by microwave irradiation. In the second stage, the silver/kappa carrageenan (AgNPs/KCar) colloid was incorporated with chitosan, and a film was made using the casting technique. The silver nanoparticles formed were validated with a UV-Vis spectrophotometer through the absorption peak at about 400 nm wavelength. FTIR spectra exhibited peaks emerging at the wavenumber 1559.89 cm^-1 – 1561.75 cm^-1, indicating the formation of the carrageenan-chitosan polyelectrolyte complex. The AgNPs/KCar-Chit hydrogel films had an average solubility of 32%-34%, swelling of 300%-304%, and the surface morphology formed aggregates. The mechanical properties were particularly affected by the incorporation of chitosan. Still, the introduction of AgNPs into the films also influenced the tensile strength, elongation, and elasticity of the AgNPs/KCar-Chit hydrogel film. Further, the greater concentration of AgNPs enhanced the antibacterial performance of the AgNPs/KCar-Chit hydrogel films.

Abstract: Temu Kunci (Kaempferia pandurata Roxb.) is one of the plants from the Zingiberaceae family that contains secondary metabolites derived from flavonoids. Studies on the bioactivity of flavonoid compounds from this species have shown various biological activities such as antibacterial, antioxidant, antiviral, antitumor, antipyretic, anti-inflammatory, analgesic, and insecticidal properties. Pinostrobin (5-hydroxy-7-methoxy flavanone) (1) is the major flavonoid found in the rhizomes of this plant and has been successfully derivatized through ethylation and allylation reactions. Two compounds were obtained from the ethylation reaction, namely 5-ethoxy-7-methoxy flavanone (2) and 4'-ethoxy-6'-methoxy chalcone (3), while from the allylation reaction, 5-allyloxy-7-methoxy flavanone (4) and 6-allyl-7-methoxy flavanone (5) were obtained. Compounds 2, 3, 4, and 5 were tested for their antibacterial activity against the Gram-positive bacterium Staphylococcus aureus ATCC 25923 and the Gram-negative bacterium Escherichia coli ATCC 25922 using the agar diffusion method. The results of the inhibition zone measurements showed that compounds 2, 3, 4, and 5 were not active against S. aureus ATCC 25923 and E. coli ATCC 25922.

Abstract: The research is intended to synthesize copper(II) with Phenobarbital (PB) complex in 1 : 4 mole ratio. The sole reflux method is designated to synthesize reactant within methanol solvent. Cu(II) complex is characterized using Atomic Absorption Spectrophotometry (AAS), UV-Vis Spectrophotometer, Fourier-transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Conductivity meter, and Magnetic Susceptibility Balance (MSB). The Cu(II)-PB complex signified 1 absorption peak at 517.5 nm with 2Eg → 2T₂g transition. Complex is then composed by 6 electron donors of Cu ion-bound ligand, forming the octahedral geometry. Complex possesses the molecule formula of [Cu(PB)₃]Cl₂, this signifies only the PB that bound to Cu(II) ion as ligand through Oxygen and Nitrogen atom donors. There is no evidence of H₂O molecules coordinated as ligand. Complex is electrolyte along with Cl^- as counter ion that neutralized the complex charge. Complex is also being paramagnetic with the value of μeff of 1.74 BM.

Abstract: Lipid metabolism is the process of breaking down triglycerides into fatty acids and glycerol, which are oxidized to provide energy. Peroxisome proliferation-activated receptor (PPAR)- alpha and adenosine monophosphate protein kinase (AMPK) are key proteins to increase endogenous lipolysis, which become important targets for weight loss management. Orange peels generally contain hesperidin and naringin compounds which can improve lipid metabolism through lipolysis, cholesterol regulation, inhibition of fat absorption, antioxidants and anti-inflammation. This study aimed to identify hesperidin and naringin compounds in Berastagi sweet orange peel extract (OPE). Berastagi sweet oranges were obtained from local market in Surakarta, Central Java, Indonesia and extracted using the maceration method with 96% (v/v) ethanol solvent. Identification of hesperidin and naringin compounds was performed by High Performance Liquid Chromatography (HPLC) and Liquid Chromatography Mass Spectrometer (LCMS) methods at the Integrated Laboratory of Universitas Sebelas Maret (UNS) and Universitas Diponegoro respectively. The results of HPLC analiysis were further calculated by using the linear regression formula to determine the concentration of the sought-after compounds. Hesperidin detected in OPE as 0.0045 mg/ml. The LCMS analysis could not detect hesperidin and naringin; however, it detected naringenin, a naringin derivate. In conclusion, OPE has low hesperidin concentration and a naringin derivate. Further studies are needed to obtain more hesperidin and naringin; for example, by using other solvents and different extraction methods.

Abstract: Pancreatic lipase plays an important role in converting triglyceride into long-chain fatty acids and glycerol, then becomes a therapeutic target for obesity treatment. Quercetin and chrysin are able to inhibit pancreatic lipase, which is potentially developed for obesity treatment. This study aimed to identify quercetin and chrysin derived from the methanol extract of raja and kepok banana peels using High Performance Liquid Chromatography (HPLC) and Liquid Chromatography Mass Spectrometer (LC-MS) for the development of obesity treatment. Raja and kepok banana peels were purchased from a fruit seller in Klaten City. Raja and kepok banana peels were extracted using the maceration method with 80% (v/v) methanol solvent. Quercetin and chrysin compounds were identified using HPLC and LC-MS at the Integrated Laboratory UNS and Universitas Diponegoro, respectively. Quercetin concentration was calculated using linear regression of diluted standard quercetin. The quercetin concentration in the raja peel extract was 0.338 mg/dL but was not detected in the kepok banana peel extract. The peak of chrysin in raja and kepok banana peel extract was not detected. LC-MS analysis identified chrysin in raja banana peel extract. In conclusion, raja banana peel extract is a potential source of quercetin and chrysin for alternative natural lipase inhibitors for obesity treatment. Further research is required carry out extraction using other solvents, isolate and purify quercetin and chrysin from raja banana peel extract, which will be used for in vitro and in vivo studies.