Growth physiology and metabolic flux of Pichia pastoris were analyzed using glass columns containing slabs of polyurethane foam as a solid support and culture medium with glycerol or glucose as a carbon source.
RESULTS
Media with glycerol produced an average of 30.91% more biomass than media where glucose was used. However, the specific growth rate registered higher values for media with glucose than those with glycerol at low substrate concentrations: 0.46 versus 0.22 h−1. Media with glycerol produced a large amount of d-arabitol, whereas ethanol and citrate were the predominant metabolites in media with glucose. Both types of culture systems generated biphasic curves in terms of the respiratory quotient value, whose inflection point coincided with the transition from aerobic metabolism to a mixed one.
Linh Dieu Nguyen, Khanh Ha Nguyen, Phat Ngoc Nguyen, Kim Nguyen Tran, Diep Dinh Le, Phuong Hoang Tran, Hai Truong Nguyen
BACKGROUND
Amorphous carbon-bearing sulfonic acid groups (AC–SO3H) are a kind of solid acid that exhibits high acidity and belongs to the new generation of solid acids. The presence of acidic functional groups, including carboxylic acid, phenolic and sulfonic acid groups, allows for several key activities such as strong Brønsted acid properties, high surface area, stability, reusability and recyclability.
RESULTS
In this work, we synthesized indolyl 1H-pyrroles from indoles, phenylglyoxal monohydrate, 1,3-diketones and ammonium acetate using rice-husk-derived carbonaceous sulfonation (AC–SO3H) as a catalyst. We explored the impact of catalyst quantity, reaction time, solvent, mineral acid and temperature in order to determine the optimal reaction conditions. Additionally, indolyl 1H-pyrrole derivatives were also synthesized based on the optimal conditions that were completely investigated, and the structure of these synthetic compounds was characterized by 1H- and 13C-nuclear magnetic resonance.
The neutrophil activating protein (NAP) is a highly immunogenic and virulence factor of Helicobacter pylori, presenting inflammatory and immunomodulatory activity. Consequently, NAP has been explored as a diagnostic and therapeutic target. However, when evaluating a target protein to design diagnostic methods or vaccines, it is critical to determine the protein conservation among the bacterial population, as well the impact of alterations of amino acid residues on the protein antigenic profile.
RESULTS
In the present work, NAP conservation and theoretical antigenicity were determined among 51 sequences from H. pylori isolated from patients worldwide. A high NAP conservation (83%) was observed, where 17 amino acid residues, among the 144 residues of the protein, were polymorphic. Alterations at these polymorphic sites had a theoretically low impact on predicted antigenicity, where only 5 NAPs out of 51 NAPs presented a slightly different antigenic profile in relation to the consensus sequence. According to that, it was possible to recognize in western blotting 93% of NAP from different bacteria (n = 15) using polyclonal antibodies developed against a specific NAP.
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Paula Valéria Viotti Moreira, Wardleison Martins Moreira, Débora Federici dos Santos, Henrique Straioto, Marcelo Fernandes Vieira
BACKGROUND
Natural zeolite's inefficiency in removing organic compounds has been a significant challenge in water treatment. To address this, this study focuses on an innovative and efficient hydrothermal process for altering the zeolitic structure. The study aimed to determine the optimal conditions for hydrothermal zeolite treatment to remove diclofenac, thereby contributing to the expansion of zeolite's potential use in water treatment.
RESULTS
The study found that modification temperature significantly affected diclofenac removal, whereas cetrimonium bromide (CTAB) concentration impacted modification yield. The conditions (150 °C, 0.374 gCTAB/gzeolite, for 6 h) were selected for their mildness and effectiveness. Characterization showed a reduction in micropores, development of mesopores and an increase in clinoptilolite content while maintaining crystallinity. Fourier transform infrared analysis and zeta potential measurements confirmed the surfactant's presence. Adsorption tests indicated that pH, except at extremely basic levels, did not affect diclofenac removal, highlighting the method's industrial applicability. The kinetic study revealed slower adsorption influenced by intraparticle diffusion. Equilibrium studies indicated spontaneous, exothermic adsorption as a result of stronger interactions between the modified adsorbent and diclofenac. The maximum adsorption capacity was 11.15 mg g−1, with hydrophobic and electrostatic interactions enhancing drug removal efficiency compared to unmodified zeolite.
Boyun Gao, Huijiang Huang, Mooeez Ur Rehman, Bin Ren, Yuruo Liu, Weipeng Fan, Pengfei Li, Lizhi Zhang, Yan Xu, Yujun Zhao
BACKGROUND
The synthesis of fatty amines via fatty alcohol amination offers a promising avenue for environmentally friendly production, particularly when compared with the methods employing hydrocyanic acid which often involve significant emissions.
RESULT
This study explores the synthesis of n-hexylamine through one-step amination of n-hexanol utilizing a series of Ru-doped Ni catalysts supported over γ-Al2O3, achieving 61% n-hexanol yield, 35% dihylamine yield and 3.5% trihylamine yield at the n-hexanol conversion of 99%.
Nasira Hussain, Muhammad Asif, Shanza Shafaat, Muhammad Saqib Khan, Nadia Riaz, Mazhar Iqbal, Abdullah Javed, Tayyab Ashfaq Butt, Ahson Jabbar Shaikh, Muhammad Bilal
BACKGROUND
Fe2O3/ZnO hybrid nanoadsorbent was synthesized by the coprecipitation method and characterized. The hydrodynamic size and stability of the nanoadsorbent were investigated in batch adsorption of toxic Reactive orange (RO)16 dye at increasing concentrations. The mechanism of monolayer and multilayer dye adsorption was elucidated for the first time together through dynamic light scattering (DLS), isotherm, kinetic and thermodynamic studies. A tomato seed germination assay was performed to confirm the material and treated water toxicity.
RESULTS
The ferromagnetic nanoadsorbent exhibited 85% RO16 dye removal. Nonlinear fitting of isotherm and kinetic models suggest the chemisorption (monolayer) and physisorption (multilayer) of dye over the heterogeneous surface of the nanoadsorbent, respectively, at lower and higher concentration of dye. In line with these mechanistic insights, DLS studies demonstrate that monolayer adsorption increased hydrodynamic size up to 100 mg L−1 by face-off binding of dye molecules, whereas multilayer adsorption was in the 100–500 mg L−1 concentration range; besides increase in adsorption capacity, did not magnify hydrodynamic size owing to face-on binding with multiple dye molecule stacking. Zeta potential data confirmed greater stability of the nanoadsorbent at solution pH with large hydrodynamic size. Thermodynamic studies suggested that endothermic and spontaneous adsorption process primarily controlled physical adsorption at higher dye concentrations. A toxicity assay proved that the nanoadsorbent and treated water are environmentally safe.
Alyaa K. Mageed, May Ali Alsaffar, Mohamed Abdel Rahman Abdel Ghany, Khalid A. Sukkar, Bamidele Victor Ayodele
Background
The mitigation of global warming effect requires intensified research efforts to reduce greenhouse gas emissions. This study was aimed at investigating the valorization of two principal greenhouse gases, namely carbon dioxide (CO2) and methane (CH4), over CeO2-doped Co–Ni/GO catalytic materials. The CeO2-doped Co–Ni/GO catalysts were synthesized using a sequential wet impregnation method and employed for CO2 reforming of CH4. The catalytic materials were characterized using various instrumental techniques. Response surface methodology (RSM) was employed to investigate the impact of process factors, namely reaction temperature (ranging from 700 to 800 °C), CeO2 loading (ranging from 5% to 15%) and feed flowrate (ranging from 10n to 50 mL min−1), on the CH4 conversions.
Results
The three factors were observed to have significant influence on the CH4 conversion based on analysis of variance. The analysis of the RSM quadratic model revealed that the optimum conditions of 800 °C, 14.22% and 10.00 mL min−1 were obtained for the reaction temperature, CeO2 loading and feed flowrate resulting in maximum CH4 conversion of 98.24%. The desirability function for these results was calculated to be 0.934. The predicted process parameters aligned with the results of the actual experimental analysis.
Tailored design of high-performance nanofiltration membranes is desirable. The physicochemical properties of the organic phaseare essential for the preparation of nanofiltration membranes. Therefore, byfine-tuning the organic phase, it is possible to achieve nanofiltrationmembranes with enhanced performance.
RESULTS
In this work, oleic acid, a naturally extracted fatty acid, wasintroduced into three different organic solvents (n-heptane, n-octane andisopar G) to construct special oil phases for interfacial polymerization. Testingresults showed that proper dosage of oleic acid addition can effectivelydecrease the nanofiltration membrane pore size and enhance the salt rejectionregardless of the solvent type. Taking n-octane as example, 5% oleic acidaddition in it can decrease the mean pore size from 0.500 nm to 0.341 nm and improve the MgSO4 rejection from 52.4% to 95.5%. Further characterizationindicated that the introduction of oleic acid into organic solvent cansignificantly reduce the interfacial tension and promote the diffusion of piperazinefrom aqueous phase to the oil phase. In addition, oleic acid could react with piperazineand produce some white particles that could be embed into the polyamide layer, thus altering the surface morphology.
LaCuMnOx (LCMO) perovskite was designed as an effective catalyst to activate peroxydisulfate (PDS) to remove bisphenol A (BPA) in hypersaline wastewater.
Results
In the LCMO/PDS system, BPA (10 mg/L) was removed completely and the mineralization degree reached 74.9% in the presence of 0.12 g/L catalyst and 1.2 mM PDS. The BPA removal efficiency was still almost 100% even after five cycles. Metal ion leakage also indicated the stability of the catalytic system. •OH, SO4•−, 1O2, and O2•− all contributed to BPA removal, and O2•− accounted for the greatest contribution. The presence of oxygen vacancies (Vo··) on the surface of the catalyst was important for PDS activation and the formation of active species. In addition, the system could still maintain outstanding performance even when [Cl−] and [SO42−] were 100 g/L. CO32− and HCO3− inhibited BPA degradation greatly, even at very low concentrations. The inhibitory effect was related to changes in the pH of the solution caused by the addition of CO32− and HCO3−. This effect could be eliminated by adjusting the pH.
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