Cerium oxide (CeO2) and Neodymium oxide (Nd2O3) nanoparticles using local content have been synthesized by precipitation method. The CeO2 and Nd2O3 nanoparticles were characterized by X-Ray Diffraction (XRD) and Fourier Transform Infrared (FTIR) to analyze the material phase and structure. The XRD spectrum shows that CeO2 and Nd2O3 nanoparticles have face-centered cubic and hexagonal, and cubic, respectively. The anti-microbial activity of CeO2 and Nd2O3 nanoparticles was analyzed by diffusion method using gram-negative bacteria (E.coli, S.aeureus, P. aeruginosa), and gram-positive bacteria (S. entericatyphi, L. monocyogenes), and fungus (C. albicans). The result confirms that CeO2 and Nd2O3 nanoparticles have the capability of patogen microbia inhibition. The CeO2 nanoparticles have the effective activities of inhibition for the microbia of S. aereus and S. entericatyphi, whereas Nd2O3 nanoparticles can inhibit the microbia of P. aeruginosa, S. entericatyphi, and L. monocyogenes.
Abstract. Ni’matuzahroh, Sari SK, Ningrum IP, Pusfita AD, Marjayandari L, Trikurniadewi N, Ibrahim SNMM, Fatimah, Nurhariyati T, Surtiningsih T, Yuliani H. 2019. The potential of indigenous bacteria from oil sludge for biosurfactant production using hydrolysate of agricultural waste. Biodiversitas 20: 1374-1379. Biosurfactants are amphipathic compounds which are useful in various fields of health, industry, and remediation. Biosurfactants are produced by bacteria that grow in hydrocarbon or sugar substrates. Hydrolysis product of agricultural waste can be used as a biosurfactant production medium. This research aims to obtain biosurfactant producing bacteria from Balongan oil sludge, Indonesia. The ability to grow and produce biosurfactant by indigenous bacteria was tested using a medium of Synthetic Mineral Water (SMW) added by 209.3 ppm of rice straw hydrolysis product (RSHP). The growth of bacteria was evaluated through Total Plate Count (TPC) and biosurfactant production was evaluated through measurement of emulsification activity and surface tension. Six indigenous bacteria were capable to produce biosurfactants in the RSHP. Emulsification activity was not detected, but surface tension reduction was founded. The best biosurfactant was indicated by surface tension value of 53.56 mN/m with TPC value of 20.07 CFU/mL at the 5th day of incubation by BP (1) 5. The indigenous bacteria were identified as Propionibacterium BP (1) 1, Propionibacterium BP (1) 3, Bacillus BP (1) 4, Corynebacterium BP (1) 5, Corynebacterium BP (1) 8, and Rothia BP (1) 6. Utilization of sugar as hydrolysis product of agricultural waste is an innovation of raw materials for biosurfactant production.
Aims: Oil sludge is one of pollutant sources in the environment. Bacterial abundance, interaction, and compatibility of environmental factors ensure the success of biodegradation. The purpose of this study was to determine the effectiveness of bacterial consortium in degrading oil sludge using bioslurry method. Methodology and results: The research design used was completely randomized design 4×5 with variation of bacterial consortium concentration and incubation time. Composition of contaminant and liquid phase in bioslurry method was 1:9 ratio with aeration, at room temperature. The liquid phase comprises distilled water with the addition of 2% (v/v) of molasses as nutrient for bacterial growth. Bacterial growth was evaluated using the Total Plate Count (TPC) method. Total Petroleum Hydrocarbon (TPH) measurements were evaluated using the gravimetric method while the oil sludge hydrocarbon component was evaluated by Gas Chromatography Mass Spectrophotometry (GCMS). The pH and temperature data were analyzed descriptively while TPC and TPH data were analyzed using Two Way ANOVA (α=0.05). The bacterial consortium could grow on oil sludge hydrocarbon substrate with a range of temperature of 29 °C-32 °C and an optimum pH of 7. Biodegradation of TPH was 70.48% at consortium concentration of 15% in 14 days of incubation. Conclusion, significance and impact of study: Biodegradation of oil sludge using a bacterial consortium by bioslurry method is one of the effective methods to reduce pollutants in the management of oil sludge.
Cerium oxide base materials have been attracting great attention as a promising electrolyte for intermediate temperature of solid oxide fuel cell (IT-SOFC) due to its excellent conductivity at a lower temperature. In this works, cerium from Indonesia local raw material was developed as a cheaper alternative precursor for preparing gadolinium doped cerium (Ce0.9Gd0.1O1.95 or GDC10) electrolyte. The effects of polyethylene glycol 400 (PEG 400) as a surfactant on to physical properties of GDC10 electrolyte were studied. GDC10 powders were synthesized using co-precipitation method with the addition of various PEG 400 concentration i.e 0,1,2 and 3v/v%. Synthesized powders were characterized by using X-Ray Diffraction (XRD), Particle Size Analyzer (PSA), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and Fourier Transform Infrared (FTIR) Spectroscopy. The XRD analysis indicates that crystallinity was enhanced and all of the peaks on samples correspond to the fluorite crystal structure of single phase CeO2. The average crystallite size is about 11.37, 7.27, 6.75 and 7.02 nm for PEG 400 concentration of 0, 1, 2 and 3v/v%, respectively. SEM images show different morphology of particle regarding with the addition of surfactant. Particle size analysis exhibits decreasing of particle diameter as the addition of PEG surfactant. The smallest particle size was about 1.47 μm for 1v/v% of PEG concentration. The results of this works confirm that the addition of PEG 400 surfactant strongly affects particle size and morphology of GDC10 powders. However, addition PEG 400 as surfactant should be delivered in a certain amount to give optimum effects where according to this works it is about 1 -2v/v%.
Biodegradation of polyaromatic hydrocarbons (PAHs) are catalyzed by multicomponent enzymes from microbe. The initial dioxygenase was used as a key enzyme for attacking the aromatic ring structure of PAHs, furthermore its initial dioxygenase gene was used to select PAHs degrading bacteria. Marine bacteria M128 strain could grow on medium contained PAHs. Detection of its cellular initial deoxygenase gene was done by nahAc gene amplification. The nahAc gene commonly used as biomarkers of PAH degradation, and as a result, nahAc gene sequence analysis of marine bacteria M128 strain was similar to naphthalene dioxygenase of Pseudomonas genera with 99% homology.
Lithium-ion battery has been drawing attention from researchers due to its excellent properties in terms of electrochemical and structural stability, low cost, and high safety feature, leading to prospective applications in electric vehicles and other large-scale applications. However, lithium-ion batteries are still in charging time owing to its low conductivity, restricting its wide applications in large-scale applications. In this work, therefore, lithium lanthanum titanate (LLTO) was synthesized derived from lanthanum oxalate, as a lanthanum source, for an anode active material application in the lithium-ion batteries due its high electrochemical conductivity and pseudocapacitive characteristics. To the best our knowledge, our work is the first one to synthesize LLTO from lanthanum oxalate as the lanthanum source. Commercial lithium carbonate and commercial titanium oxide were used as the lithium and titanium sources, respectively. It was used low cost and simple solid-state reaction process to synthesize this material and performed a two-step calcination processs at 800 oC for 8 hours and 1050 oC for 12 hours under ambient atmosphere. The physical characteristics showed that LLTO possesses high purity (98.141%) and micro sized grains with abundant empty spaces between the grains. This, therefore, lead to improve electrochemical performances such as stable discharge capacity at low potential even near to zero (98.67 mAh), and a high conductivity of 2.45 × 10-2 S/cm at room temperature. This LLTO is interesting to be used as the anode active material in low potential lithium-ion battery applications.
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