Makara Journal of Science
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Characterization of Protease from Bacillus licheniformis F11.1 as a Bio-Detergent Agent
No full textProteases are among the most important enzymes in both food and non-food industries taking up almost 60% of the world enzyme market. This enzyme has been used for many industrial processes, especially in the detergent industry. The purpose of this study was to characterize the protease from Bacillus licheniformis F11.1 as a bio-detergent agent. An enzyme assay of protease activity was used to assess and characterize the protease enzyme from B. licheniformis F11.1. It showed that the highest pH protease activity for alkaline protease occurred at pH 8.0 with a value of 35.00 U/mL. Under incubation temperature, the protease had the highest activity at 50 °C with a value of 24.46 U/mL. Protease activity was inhibited by Ca2+, Mn2+, K+, and Na+ ions at concentrations of 5 mM. Protease activity can be enhanced by these ions at concentrations of 2 mM. Protease stability can be measured from half-life. Under an incubation temperature of 50 °C, the half- life of the protease at pH 8, 9, and 10 was 108 min, 114 min, and 98 min, respectively. The assay for enzyme stability with an incubation temperature of 60 °C showed half-lives of 92 minutes, 56 minutes, and 61 minutes for pH 6, 9, and 10, respectively. This enzyme was found to be stable with the addition of detergent compounds such as sodium dodecyl sulfate (SDS), Triton X-100, ethylenediaminetetraacetic acid (EDTA), and hydrogen peroxide; all under low concentrations. Determination of the molecular weight using SDS- PAGE and zymogram found the molecular weight was 32.90-35.16 kDa. These results showed that the alkaline protease from B. licheniformis F11.1 can be used as a bio-detergent because of its tolerance to various detergent compounds
Comprehensive Theoretical Studies on 11-MeV Proton Based Tc-99m Production
No full textThe shortage of nuclear-reactor-based Tc-99m supply has led to increased research on cyclotron-based Tc-99m production. In this paper, Tc-99m radionuclides produced by a 11-MeV proton cyclotron is theoretically discussed in terms of the optimum thickness of natMo, natMoO3, and enriched 100Mo targets; expected impurities; and radioactivity yields of several (p,2n), (p,n), and (p,γ) based nuclear reactions. The SRIM 2013 codes and TALYS 2014 codes are employed to calculate the range of 11-MeV proton beams in the Mo-based targets and the excitation functions of the selected nuclear reactions, respectively. The calculated results indicate that 94m,95m,96mTc radionuclides would give rise to radionuclide impurities at the end of irradiation for natMo targets, whereas no significant impurities were theoretically detected for the enriched 100Mo target. At the end of bombardment, nearly 42.18 GBq/µA.hr of Tc-99m radionuclide is predicted to result in the 11-MeV proton-irradiated 100Mo target. 
High Levels of Resistance in A Culex quinquefasciatus Population to the Insecticide Permethrin in Filariasis Endemic Areas in Central Java
No full textResistance among Culex mosquitoes to various insecticides has been reported in many countries. However, there have been no studies of the resistance status of Culex in Indonesia. There is a need for such studies to develop a database for use in vector control management. This study aimed to investigate the insecticide resistance status of C. quenquefasciatus, which is the primary vector of filariasis, to aid the planning of a vector control management program. In the present study, Culex quinquefasciatus larvae were collected from five districts/municipalities where filariasis is endemic in Central Java. The larvae were reared to adult stage, and insecticide susceptibility testing was then conducted according to standard bioassay procedures of the World Health Organization (WHO). The results of the bioassays showed that C. quinquefasciatus had a high level of resistance against 0.75% permethrin, with mortality rates ranging from 4.8 to 21.6%. The lowest resistance was found among mosquitoes collected from Grobogan district. This may be explained by the district’s remote geographical location. The high level of resistance found in the present study may be caused by exposure to local insecticides, which have been applied for many years as part of a dengue vector control program. These insecticides may also have contaminated the breeding sites of C. quinquefasciatus mosquitoes. Better vector control management is needed to help prevent the development and spread of resistance. Such management should include routine insecticide surveillance and insecticide alternation
Studies of Power Conversion Efficiency and Optical Properties of Ni3Pb2S2 Thin Films
No full textNi3Pb2S2 thin films were prepared by using a chemical bath deposition method. In this work, solar cells were fabricated using these materials as absorber layers. Power conversion efficiency testing will be carried out. The results show that these absorbent materials exhibit an open circuit voltage of 0.61 V, a short circuit current density of 9.9 mA/cm2, a fill factor of 0.47 and a power conversion efficiency of 2.7%. 
Biospeciation of Cr(III) Nutritional Supplements in Biological Fluids
No full textMetal ion speciation in various biological systems has been extensively studied to elucidate its biological role and the toxicity of the element of interest. In the present study, chromium speciation was performed by reacting Cr(III) nutritional supplements [Cr(pic)3], where pic = 2 pyridinecarboxylato(-), and a Cr(III) propionate complex, [Cr3O(OCOEt)6(OH2)3])+, in calf serum. Cr(III) complexes in serum were fractionated using size-exclusion chromatography, and the Cr(III) concentrations in each fraction were determined using graphite furnace atomic absorption spectroscopy. The results showed that Cr(III) bound to both high- and low-molecular weight serum fractions. While Cr(III) was mainly bound to albumin or transferrin, unknown low-molecular-weight serum fractions were also important in Cr binding. The Cr(III) distribution in serum fractions was found to be time-dependent.  
Characteristics and Ideotype Formulation of Pulasan (Nephelium ramboutan-ake) Fruit Landrace from West Java, Indonesia
No full textPulasan (Nephelium ramboutan-ake) is a unique tropical fruit, but its morphological variations have not been well characterized. This study was conducted to obtain data on the characteristics of pulasan landrace in West Java, Indonesia, and to formulate the ideotype of pulasan with superior characteristics, such as high fruit weight, sweet taste, and thick and easily peelable aril from the seed. Based on the descriptors of rambutan, 61 fruit variants were observed. The results showed that the average fruit weight was 46.0 g, with the highest at 103.5 g and the lowest at 23.1 g. The °Brix level variation of pulasan fruit was 16.8–29.6, and its vitamin C content was 14.0–24.0 mg/100 g. Five variants with superior fruit characters were identified among the sample collections used in the study
Biodegradation of Used Synthetic Lubricating Oil by Brevundimonas diminuta AKL 1.6
No full textIllegal disposal of used lubricating oil is a serious hazard to the environment and public health. This study is aimed at examining the biodegradation process of used synthetic lubricant using local microorganism. Oil-degrading microorganism were obtained from sea water contaminated with used lubricating oil. Those that showed some growth activity in Bushnell-Haas media containing used synthetic lubricating oil as a sole carbon source were selected. Its single colony was then generated by performing the dilution and scratch technique in the isolation and purification process. By using 16s rDNA, a potential strain namely AKL 1.6, was identified as Brevundimonas diminuta. Gas chromatography analysis was performed before and after the biodegradation process of the used oil. As a result, B. diminuta AKL 1.6 was found to utilize used synthetic lubricating oil as the sole source of carbon and to degrade most of the hydrocarbon within the oil for 14 days. Thus, this particular microorganism has the potential to be the single microbe for bioremediation of sea water contaminated by lubricating oil
Nutrient Accumulation in the Sediment of Silvofishery Ponds in Semarang
No full textInformation concerning the functionality of mangrove within silvofishery ponds is needed, especially relating to the accumulation rate of organic materials and nutrients. This research studied the effect of mangrove structure on the accumulation rate of nutrients within silvifishery ponds. The research, conducted in May 2016, used canals of width 1, 2, and 3 m, with mangrove species Avicennia marina and Rhizophora mucronata, alone or in combination. Nutrients measured were nitrogen, phosphorus and organic matter, in the sediment of the treatment ponds, through soil sampling followed by laboratory analysis. The respective analysis methods used were Kjehdahl, spectrophotometry, and ashing. Data analysis was conducted using factorial ANOVA. The highest nitrogen concentration was detected in the treatment with 15 stands of mixed mangrove species (0.63 ± 0.04 %), the treatment with 10 stands of mixed mangroves showed the highest phosphorus concentration (62.86 ± 12.31 mg/kg), and the highest organic matter concentration (2.55 ± 0.67 %) was seen with 10 stands of R. mucronata. The highest average value based on partial group showed that R. mucronata had the highest nitrogen accumulation at 0.56 ± 0.07 %; for phosphorus, the mixed species pond (62.02 ± 7.84 mg/kg); and for organic matter, R. mucronata (2.41 ± 0.39 %)
UV-Visible Optical Absorbance of Graphene Oxide Synthesized from Zinc-Carbon Battery Waste via a Custom-Made Ultrasound Generator based on Liquid Sonication Exfoliation Method
No full textThe objectives of this study are i) to synthesize graphene oxide (GO) from the waste materials of zinc-carbon (ZnC) batteries via the liquid sonication exfoliation (LSE) method using tweeter piezoelectric probes as speakers, and ii) to study the optical absorbance of the GO produced using a UV-Vis spectrophotometer by varying the mass of the graphite materials obtained from ZnC battery waste. The graphite materials are obtained from the carbon rods of the ZnC batteries, which are ground into powder. The powder is then mixed with distilled water, with powder mass variations of 0.4, 0.6, 0.8, and 1.0 grams. The solutions obtained are sonicated with a frequency of 30 kHz for six hours using a custom-made ultrasound generator based on piezoelectric probes. The effect of graphite material mass variation is studied by observing the UV-Vis spectrophotometer data before and after sonication. The results of this study show absorbance peaks at wavelengths of 221 nm to 227.5 nm, and shouldering peaks at 260 nm to 270 nm, indicating the presence of GO materials for all graphite mass variations. The best GO performances based on the UV-Vis results are obtained in samples with 0.8 and 1.0 grams of graphite powder, which undergo a red shift from 223.5 nm to 227.5 nm, respectively. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) are conducted upon the sample of 1.0 grams of graphite powder before and after sonication treatment. The SEM results before sonication show graphite materials forming in large chunks, whereas after sonication smaller islands of GO materials consisting of thin, transparent flakes are observed. The EDX results reveal that the sample material after sonication consists of 88% carbon, 11% oxygen, and a remaining 1% of aluminum, silicon, sulphur, ferrum, and zin
The use of Carbon Compounds (Carbon Nanotubes and Activated Carbon) in the Improvement of TiO2–Carbon Supercapacitor Performance
No full textImprovement of the performance of titanium oxide (TiO2)–carbon supercapacitor was studied by fabricating a double-layer electrode composite consisting of (TiO2), activated carbon (AC), and carbon nanotubes (CNTs). A thin layer of TiO2/CNT/AC electrode was coated on an aluminum foil substrate through the addition of a polyvynilidene fluoride adhesive of around 15% of the total weight of the composite. The resultant layer was then made into a double layer, and its conductivity and capacitance were measured using the electrochemical impedance spectroscopy (EIS). Results showed that the supercapacitor performance improved with the addition of CNTs. The highest performance was obtained with a composition of 23.3% TiO2, 21.0% CNT, and 4.0% AC with a 1.29 × 10-2 S/m conductivity and 5.56 F/g capacitance (C) at a frequency of 0.1 Hz