Amino Acid Salt Research Articles

Neural modeling and simulation of molecular separation using amino acid salt solutions

In this research paper, we studied absorption of carbon dioxide in amino acid solutions theoretically via the artificial intelligence (AI) method. The CO2 loadings in different solutions were predicted as a function of input parameters including amino acid parameters and operational parameters such as pressure and temperature. For the training of the data, we used differential evolution, and for the decision and prediction sections, we used the fuzzy interface system. The model can be abbreviated as differential evolution fuzzy interface system (DEFIS). Moreover, various methods and tuning parameters in the DEFIS were used to increase the accuracy of the model. Cluster influence range (CIR) was used for tuning the model, and different population sizes were used, including 9, 18, 27, and 36, with the purpose of observing the effects of these parameters on the training. The results from AI overlapped measured results meaning that we can use AI for optimization of the separation process for CO2 sorption in chemical solvents. The neural methodology indicated a reliable and robust prediction of CO2 solubility in different chemical solvents.

Evaluation of CO2 Absorption by Amino Acid Salt Aqueous Solution Using Hybrid Soft Computing Methods.

Amino acid salt (AAs) aqueous solutions have recently exhibited a great potential in CO2 absorption from various gas mixtures. In this work, four hybrid machine learning methods were developed to evaluate 626 CO2 and AAs equilibrium data for different aqueous solutions of AAs (potassium sarcosinate, potassium l-asparaginate, potassium l-glutaminate, sodium l-phenylalanine, sodium glycinate, and potassium lysinate) gathered from reliable references. The models are the hybrids of the least squares support vector machine and coupled simulated annealing optimization algorithm, radial basis function neural network (RBF-NN), particle swarm optimization–adaptive neuro-fuzzy inference system, and hybrid adaptive neuro-fuzzy inference system. The inputs of the models are the CO2 partial pressure, temperature, mass concentration in the aqueous solution, molecular weight of AAs, hydrogen bond donor count, hydrogen bond acceptor count, rotatable bond count, heavy atom count, and complexity, and the CO2 loading capacity of AAs aqueous solution is considered as the output of the models. The accuracies of the models’ results were verified through graphical and statistical analyses. RBF-NN performance is promising and surpassed that of other models in estimating the CO2 loading capacities of AAs aqueous solutions.

Insights into dual functions of amino acid salts as CO2 carriers and CaCO3 regulators for integrated CO2 absorption and mineralisation

Integrated CO2 absorption and mineralisation (IAM) is a promising technology for rapidly CO2 absorption and sequestration. However, the traditional IAM using alkanolamines as CO2 solvents and solid wastes as carbonation feedstocks still suffers from the utilization difficulty of low value products and environmental risks of amine degradation. In this study, the green solvent, amino acid salts (AAS), including potassium l-argininate (ArgK), potassium glycinate, potassium sarcosinate, potassium l-alaninate, potassium β-alaninate, were selected for IAM using rejected brine as the carbonation feedstock. Results shows that compared to amines (monoethanolamine, diethanolamine, N-methyldiethanolamine, triethanolamine, piperazine, 2-amino-2-methy-1-propanol), the selected AASs in IAM were not only more effective CO2 carriers that passed CO2 to calcium ions to form CaCO3, but also better CaCO3 growth regulators to tune morphology properties of products. CO2 desorption efficiencies in CO2-loaded AASs (nearly 100 %) were much higher than those of in CO2-loaded amines especially than in MEA (38 %). ArgK stood out in regulating the morphology of crystal with smallest particle size. Then ArgK was selected for optimization experiments at various conditions (temperature, Ca2+/CO2 ratio, reactant concentration and chelating agent) to further investigate effects of operating conditions on CaCO3 properties and to provide some basic information for the polymorph and morphology regulation of CaCO3. Ethylene diamine tetraacetic acid (EDTA) as a chelating agent was found a notable influence on controlling the polymorph of CaCO3, where the amorphous CaCO3 and new structures of calcite appeared. However, the effect of EDTA on CO2 absorption step was not clear and required further investigation.

Effect of chelates on gilts' colon microbiocenosis

Mineral additives in the form of inorganic salts such as sulfates or oxides of various metals are poorly absorbed by the body. At the same time, the assimilation of salts of organic amino acids, which are more similar in structure to a living cell, occurs in a much greater volume, indicating that many organic forms of trace elements are more accessible than inorganic ones. The analysis and study of the effect of the mineral complex based on L-aspartic acid on the microbiological state of the contents of the rectum of pigs was carried out. The use of asparaginates in the diets in an amount of 10% contributed to the normalization of the microbiocenosis of the large intestine of animals, due to the creation of the most optimal conditions for the development of normal flora (lacto-and bifidobacteria) and a simultaneous slowdown in the reproduction of opportunistic microflora.

Seawater Desalination with an Amine-based CO2-Capture Process

A new concept for seawater desalination integrated into an amine-based CO2-capture process is presented. It is based on the use of forward osmosis to transfer water from seawater into the absorption solution via a membrane. Desalted water can subsequently be recovered as the condensate from the desorber outlet or through membrane distillation from the absorber. Suitable membranes have been identified and the most promising one was selected for laboratory evaluation using representative amine solutions. The process performance parameters, membrane water flux and reverse amine flux were determined. The process performance was best for amino-acid salt solutions. Further work will focus on demonstration of the technology using a post-combustion CO2 capture pilot plant operating on real flue gas.

Genomic Evolution and Variation of SARS-CoV-2 in the Early Phase of COVID-19 Pandemic in Guangdong Province, China.

SummarySevere acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) with unknown origin spread rapidly to 222 countries, areas or territories. To investigate the genomic evolution and variation in the early phase of COVID-19 pandemic in Guangdong, 60 specimens of SARS-CoV-2 were used to perform whole genome sequencing, and genomics, amino acid variation and Spike protein structure modeling analyses. Phylogenetic analysis suggested that the early variation in the SARS-CoV-2 genome was still intra-species, with no evolution to other coronaviruses. There were one to seven nucleotide variations (SNVs) in each genome and all SNVs were distributed in various fragments of the genome. The Spike protein bound with human receptor, an amino acid salt bridge and a potential furin cleavage site were found in the SARS-CoV-2 using molecular modeling. Our study clarified the characteristics of SARS-CoV-2 genomic evolution, variation and Spike protein structure in the early phase of local cases in Guangdong, which provided reference for generating prevention and control strategies and tracing the source of new outbreaks.

Expression and characterization of a thermotolerant and pH-stable hyaluronate lyase from Thermasporomyces composti DSM22891

Hyaluronate lyases have received extensive attention due to their applications in medical science, drug and biochemical engineering. However, few thermotolerant and pH-stable hyaluronate lyases have been found. In this study, hyaluronate lyase TcHly8B from Thermasporomyces composti DSM22891 was expressed in Escherichia coli BL21(DE3), purified, and characterized. Phylogenetic analysis revealed that TcHly8B belonged to a new subfamily in PL8. The molecular mass of recombinant TcHly8B determined by SDS-PAGE was approximately 86 kDa. The optimal temperature of TcHly8B was 70 °C, which was higher than that of previously reported hyaluronate lyases. TcHly8B was very stable at temperatures from 0 to 60 °C. The optimal pH of TcHly8B was 6.6. It could retain more than 80% of its original enzyme activity after incubation for 12 h in the pH range of 3.0–10.6. TcHly8B degraded hyaluronic acid into unsaturated disaccharides as the end products. The amino acid sequence and structure analysis of TcHly8B demonstrated that the amino acid composition and salt bridges might contribute to the thermostability of TcHly8B. Overall, this study provides an excellent example for the discovery of thermotolerant hyaluronate lyases and can be applied to the industrialized production and basic research of hyaluronate oligosaccharides.

Evaluation of potassium glycinate, potassium lysinate, potassium sarcosinate and potassium threonate solutions in CO2 capture using membranes

The mitigation process of greenhouse gases emission such as CO2 into the atmosphere is known as a vital necessity in modern societies. Nowadays, amino acid salt solutions (AASSs) have been extensively applied as a promising alternative to alkanol amine absorbents to increase the CO2 sequestration efficiency from disparate gaseous flows. This article aims to computationally and theoretically evaluate the CO2 separation percentage using potassium glycinate (PG), potassium lysinate (PL), potassium sarcosinate (PS) and potassium threonate (PT) amino acid solutions from an inlet gaseous mixture inside a hydrophobic membrane contactor (HMC). To do this, the governing first principal equations inside the HMC are solved using the computational fluid dynamics procedure based on finite element technique. Acceptable agreement between the simulation results and experimental values with average deviation of approximately 3% implies the validation of developed two-dimensional (2D) simulation approach developed in this study. The analysis of obtained results demonstrated that PG is the most efficient amino acid solution for CO2 molecular sequestration with the ability of separating 90% of inlet CO2 in the system. The order of solutions is 90% sequestration using PG > 89.3% sequestration using PT > 77.4% sequestration using PL > 72.3% sequestration using PS.

Next generation amino acid technology for CO2 capture

A flexible strategy to prepare a scalable CO2 absorbent (LAHPs) via encapsulating amino acid salt solutions in a polymer matrix.

Visible-light-induced iodine-anion-catalyzed decarboxylative/deaminative C–H alkylation of enamides

An efficient method for photo-induced iodine-anion-catalyzed C–H alkylation of enamides has been developed. Redox-active esters and Katritzky salts of amino acids are amenable, successfully delivering various functionalized enamides.

The application of amino acid ionic liquids as additives in the ultrasound-assisted extraction of plant material.

The aim of the present study was to determine the antioxidant activity of the aqueous extracts from Lycopodium clavatum, Cetraria islandica and Dipsacus fullonum obtained using aqueous solutions of ionic liquids by the ultrasound-assisted extraction (IL-UAE) method. Triethanolammonium salts [TEAH]+[AA]− of four amino acids of different hydrophobicity – isoleucine – Ile, methionine – Met, threonine – Thr and arginine – Arg, were chosen as ionic liquids, because they are based on natural, bio-renewable raw materials, such as amino acids and contain a pharmaceutically and cosmetically acceptable counterion of triethanolamine. Triethanolammonium salts were synthesized, identified by spectroscopic methods (NMR and FT-IR) and characterized by thermal methods (DSC and TGA). The 2.5% w/v aqueous solutions of triethanolammonium amino acid salts were used as the solvents in combination with ultrasound assisted extraction (UAE). The estimation of antioxidant properties was carried out using the DPPH, FRAP and CUPRAC assays. Total polyphenol content was measured using the reagent Folin–Ciocalteu. The results showed that the use of [TEAH]+[Thr]− or [TEAH]+[Met]− aqueous solutions increased the antioxidant activity of extracts in comparison to that achieved for extracts with pure water. The use of [TEAH]+[Thr]− as an additive for ultrasound-assisted extraction was characterized by obtaining plant extracts with the highest antioxidant potential, even 2.4-fold. The use of the AAIL-UAE method allowed obtaining higher amounts of polyphenols compared to pure water extracts, even 5.5-fold. The used method allowed the extraction of thermosensitive natural compounds, shortened the extraction time and lowered energy consumption.

Correlation of the bacterial communities with umami components, and chemical characteristics in Zhejiang xuecai and fermented brine

Xuecai is a Chinese-fermented vegetable product that has attracted much attention because of its unique umami taste. However, investigations of the bacterial communities, umami components and chemical characteristics in xuecai and the brine have not yet been conducted. In this study, the bacterial communities and their correlations with the umami components and the chemical characteristics are investigated. The results showed that significantly higher contents of total protein, total acid, amino acid nitrogen, total sugar, titratable acidity, salt, amino acids and organic acids, as well as significantly lower nitrite concentrations were observed in the brine samples. The supervised pattern recognition method revealed that the xuecai and brine could be distinguished by these indicators. In addition, the xuecai and brine were both dominated by Lactobacillus, Halanaerobium and Halomonas. A correlation analysis showed that halophilic bacteria had a positive effect on the umami components and chemical characteristics of the xuecai and brine. However, lactic acid bacteria both showed a negative correlation with amino acids and most organic acids. Membrane transport, carbohydrate metabolism and amino acid metabolism were the most abundant pathways. These results enhance our understanding of the bacterial communities, as well as the umami components and chemical characteristics in Zhejiang xuecai and brine.

Machine Learning Analysis of the Thermodynamic Responses of In Situ Dielectric Spectroscopy Data in Amino Acids and Inorganic Electrolytes.

Dielectric spectroscopy (DS) can be a robust in situ technique for geochemical applications. In this study, we applied deep-learning techniques to DS measurement data to enable rapid science interrogation and identification of electrolyte solutions containing salts and amino acids over a wide temperature range (20 to -60 °C). For the purpose of searching for signs of life, detecting amino acids is a fundamental high priority for field and planetary instruments as amino acids are one of the building blocks for life as we know it. A convolutional neural network (CNN) with channel-wise one-dimensional filters is proposed to fulfill the task, using the DS data of amino acid and inorganic salt solutions. Experimental results show that the CNN with two convolutional layers and one fully connected layer can effectively differentiate solutions containing amino acids from those containing salts in both the liquid and solid (water ice) states. To complement the experimental measurements and CNN analysis, the diffusive behaviors of ions (K+, Cl-, and OH-) were further discussed with atomistic molecular dynamics simulations performed in this work as well as the quantum simulation published in the literature. Combining DS with machine-learning techniques and simulations will greatly facilitate more real-time decision-making of mobility systems for future exploratory endeavors in other worlds beyond Earth.

Изучение антиоксидантной, антикоагулянтной и антиагрегантной активности ряда алифатических и ароматических аминокислот

Among the nitrogen-containing organic substances there are compounds with a dual function. Particularly important are amino acids. Strictly speaking, amino acids make up only one of the many families of organic compounds. Any organic molecule having at least one amino and one acid group may be assigned to this family. This generally means any hydrocarbon chain that may be branched, with or without other functional groups, aromatic rings, or any other organic structure. Therefore, it becomes clear that the number of amino acids that can be imagined is infinite. Today in Russia there is an urgent need to develop new and effective drugs for the treatment of various diseases. This important task involves organizing the production of new competitive domestic medicines on the market, the development of which is carried out on the basis of the results of fundamental scientific research in the field of organic synthesis. In this regard, derivatives and salts of amino acids are of great interest, due to their high reactivity and wide use in medical practice. We have studied the effect on the hemostasis system of derivatives based on amino acid salts, which is currently a key task of organic, bioorganic and medicinal chemistry. Consideration of the scientific literature on this topic showed the saturation and increasing interest in the influence of amino acid compounds throughout the world. The synthesis of amino acid salts and the study of their effect on the blood curability system was carried out, optimal synthesis methods for an organic compound were developed. Preliminary in vitro preclinical studies of the obtained compounds were carried out in order to find out the prospects for their further use.

Dipeptide Synthesis from S-2-Formyl-4-Nitrophenyl Thioesters and Amino Acid Salts

Dipeptide Synthesis from S-2-Formyl-4-Nitrophenyl Thioesters and Amino Acid Salts

Comparison of co-former performance in co-amorphous formulations: Single amino acids, amino acid physical mixtures, amino acid salts and dipeptides as co-formers

Co-amorphous systems have been shown to be a potential approach to address the poor water solubility challenge of many drugs. Various low molecular weight molecules, especially amino acids, have been used as potential co-formers. In this study, the differences between various combinations of amino acid-based systems, i.e. the single amino acids glutamic acid (Glu) and arginine (Arg), their physical mixture, glutamic acid-arginine crystalline and amorphous salts, and the corresponding dipeptides (GluArg, ArgGlu), were investigated. Mebendazole (Meb) was used as the model drug. Pure Meb and Meb-co-former mixtures were ball milled to prepare the co-amorphous samples. The shortest amorphization time upon ball milling (30 min) was found for Meb mixtures with the dipeptides and the Glu·Arg amorphous salt. All other samples became amorphous upon milling for 90 min, except Meb-Glu, where Glu remained partially crystalline. Both, single-phase (Meb-Glu-Arg ternary mixtures) and two-phase amorphous systems (Meb-Arg, Meb-GluArg, Meb-ArgGlu) were obtained for different Meb-co-former mixtures after milling. Whilst all co-formers improved the dissolution rate of Meb in a similar fashion (dissolution rate increased by 3.5 to 5.7-fold with respect to crystalline Meb), the highest stability improvement was observed for Meb-dipeptide systems. Interestingly, even though being a two-phase amorphous system, dipeptides were superior to the other co-formers as they possessed higher physical stability.

Carbon dioxide capture using liquid absorption methods: a review

Anthropogenic emissions of greenhouse gases into the atmosphere is inducing global warming, ocean acidification, polar ice melting, rise in sea level, droughts and hurricanes, thus threatening human health and the global economy. Therefore, there is a need to develop cost-effective technologies for CO2 capture. For instance, solution absorption is promising due to a large processing capacity, high flexibility and reliability, and rich experience in engineering applications. Nonetheless, actual commercial solutions, solvents and processes for CO2 capture suffer from slow reaction kinetics, low absorption capacity, high-energy consumption, susceptibility to corrosion, toxicity, low stability and high costs. Therefore, current research focuses on developing more economical, effective, green and sustainable technologies. Here we review 2015–2020 findings on CO2 capture using liquid absorption methods. Methods are based on various solutions, solvents and processes such as carbonate solution, ammonia solution, amine-based solution, ionic liquid, amino acid salt, phase changing absorbent, microcapsulated and membrane absorption, nanofluids and phenoxide salt solution. We discuss absorption performance, absorption mechanism, enhancement pathways and challenges. Amine- and NH3-based absorbents are widely used, yet they are limited by high regeneration energy, corrosiveness and degradation, reagent loss and secondary pollution caused by NH3 escape. Phase changing absorbents are getting more attention due to their lower cost and lower energy penalty. The incorporation of membrane and microencapsulation technologies to absorbing solvents could enhance CO2 absorption performance by reducing corrosion and increasing selectivity. Adding nanoparticles to solvents could improve CO2 absorption performance and reduce energy requirement. Besides, solvent blends and promoter-improved solvents performed better than single and non-promoted solvents because they combine the benefits of individual solvents and promoters.

Reaction mechanisms of carbon dioxide capture by amino acid salt and desorption by heat or mineralization

The reaction mechanisms of potassium glycine (KG)–CO2 absorption, thermal desorption and mineralization desorption with CaO were studied based on the contents of carbamate, bicarbonate/carbonate, and KG/protonated KG analyzed by 13C-quantitative nuclear magnetic resonance (13C qNMR). KG as the absorbent shows the CO2 absorption efficiency up to 76% which has 57% due to the bicarbonate/carbonate formation and 43% due to the carbamate formation. Mineralization has a higher CO2 desorption efficiency of 59% than that of thermal desorption (47%), and the results also indicate that carbamate is less stable under mineralization than under heat although both processes show the similar profiles as a function of pH value for carbamate and bicarbonate/carbonate. A new mechanism has been proposed to explain carbamate increasing with significantly decreasing bicarbonate/carbonate at the early stage of mineralization desorption while the other mechanisms reported in literatures have also been confirmed in this study.

State-of-the-art of CO2 capture with amino acid salt solutions

Abstract The emission of large amounts of CO2 into the atmosphere is believed to be a major reason behind climate change, which has led to increased demand for CO2 capture. Postcombustion CO2 capture with chemical solvent is considered one of the most important technologies in order to reduce CO2 emission. Amino acid salt solutions have attracted special attention in recent years due to their excellent physicochemical properties, e.g., low volatility, less toxicity, and high oxidative stability, as well as capture performance comparable with conventional amines. In this study, physicochemical properties of 20 amino acids are reported and their CO2 absorption performance discussed. The topics covered in this review include the most relevant properties of amino acids including CO2 loading capacity, cyclic capacity, equilibrium constant, density, viscosity, dissociation constant, CO2 solubility, CO2 diffusivity, reaction kinetic between CO2 and amino acid salts, reaction rate constant, surface tension, heat of CO2 absorption, precipitation, toxicity, solvent degradation, and corrosion rate. This review provides the most recent information available in the literature on the potential of using amino acid salts as a solvent for CO2 capture which can help improve the performance of the CO2 capture process from flue gas streams.

Well-Defined Construction of Functional Macromolecular Architectures Based on Polymerization of Amino Acid Urethanes.

Polypeptide synthesis was accomplished using the urethane derivatives of amino acids as monomers, which can be easily prepared, purified, and stored at ambient temperature without the requirement for special precautions. The urethanes of amino acids are readily synthesized by the N-carbamoylation of onium salts of amino acids using diphenyl carbonate (DPC). The prepared urethanes are then efficiently cyclized to produce amino acid N-carboxyanhydrides (NCAs). Thereafter, in the presence of primary amines, the ring-opening polymerization (ROP) of NCAs is initiated using the amines, to yield polypeptides with controlled molecular weights. The polypeptides have propagating chains bearing reactive amino groups and initiating chain ends endowed with functional moieties that originate from the amines. Aiming to benefit from these interesting characteristics of the polypeptide synthesis using the urethanes of amino acids, various macromolecular architectures containing polypeptide components have been constructed and applied as biofunctional materials in highly efficient antifouling coatings against proteins and cells, as biosensors for specific molecules, and in targeted drug delivery.