Kinetics Of Hydrolysis Research Articles

Study of Hydrolysis Kinetics and Synthesis of Single Isomer of Phosphoramidate ProTide-Acyclovir

Study of Hydrolysis Kinetics and Synthesis of Single Isomer of Phosphoramidate ProTide-Acyclovir

Activity-Based Dicyanoisophorone Derivatives: Fluorogenic Toolbox Enables Direct Visualization and Monitoring of Esterase Activity in Tumor Models.

The visualization and spatiotemporal monitoring of endogenous esterase activity are crucial for clinical diagnostics and treatment of liver diseases. Our research adopts a novel substrate hydrolysis-enzymatic activity (SHEA) approach using dicyanoisophorone-based fluorogenic ester substrates DCIP-R (R = R1-R6) to evaluate esterase preferences on diverse substrate libraries. Esterase-mediated hydrolysis yielded fluorescent DCIP-OH with a nanomolar detection limit in vitro. These probes effectively monitor ester hydrolysis kinetics with a turnover number of 4.73 s-1 and catalytic efficiency (kcat/Km) of 106 M-1 s-1 (DCIP-R1). Comparative studies utilizing two-photon imaging have indicated that substrates containing alkyl groups (DCIP-R1) as recognition elements exhibit enhanced enzymatic cleavage compared to those containing phenyl substitution on alkyl chains (DCIP-R4). Time-dependent variations in endogenous esterase levels were tracked in healthy and liver tumor models, especially in diethylnitrosamine (DEN)-induced tumors and HepG2-transplanted liver tumors. Overall, fluorescence signal quantifications demonstrated the excellent proficiency of DCIP-R1 in detecting esterase activity both in vitro and in vivo, showing promising potential for biomedical applications.

A Cell-Free Kinetic Analysis of Ionizable Lipid Hydrolysis.

The prolonged retention of ionizable lipids within the body limits the repeated dosing of lipid nanoparticles (LNPs) for nucleic acid delivery. While most ionizable lipids are primarily metabolized in the liver via the enzymatic hydrolysis of ester bonds, elimination half-lives can range from several hours to days. The development of compounds that undergo rapid biodegradation remains a major engineering challenge in the absence of standardized biodegradability assessments in the early stages of drug discovery. Here, we analyze and compare the hydrolysis kinetics of well-known ionizable lipids (ALC-0315, DLin-MC3-DMA, LP-01, L319, and SM-102) using optimized cell-free reactions monitored by 1H NMR. Unlike conventional analytical techniques, these NMR-based methods are universal and suitable for high-throughput screening. We demonstrate that enzyme-catalyzed and base hydrolysis reactions can predict whether ionizable lipids undergo fast or slow liver elimination, as our results are in alignment with prior pharmacokinetic studies. Furthermore, we show that the hydrolysis kinetics of ionizable lipids vary by several orders of magnitude depending on steric effects. This study provides a framework to expedite the discovery of rapidly degradable ionizable lipids, with implications for improving the therapeutic index of LNP-based drugs.

A Kinetic Study on Chronic Response of Activated Sludge to Diclofenac by Respirometry

The present study investigated the chronic response of activated sludge to the emerging pollutant diclofenac as well as its aerobic biodegradation potential at different sludge retention times (SRTs). The impact of prolonged exposure to diclofenac on microbial process kinetics was explored with respirometric modelling. The long-term operation of lab-scale reactors revealed that continuous feeding of diclofenac at relevant concentrations observed in municipal wastewaters did not affect carbon removal efficiency independentl of SRT. However, in case of diclofenac removal, 34% efficiency could be achieved at a higher SRT of 20 days. Kinetic evaluation showed that the increment in diclofenac dosing resulted in no adverse effect on the microbial growth rate except that high concentrations of diclofenac exposure decreased the growth rate at SRT of 10 days. A significant increase in hydrolysis rate was determined in the diclofenac-acclimated biomass for both SRTs; even at high concentrations of diclofenac exposure, the hydrolysis rate remained unchanged. Long-term acclimation to diclofenac had a progressive impact on the hydrolysis kinetics, which could be attributed to an alteration in the microbial culture profile. Overall, the results suggest that the operation with diclofenac-acclimated biomass at higher SRTs could enrich a microbial culture capable of overcoming the adverse effect of the pollutant and improve the biodegradation potential as well.

Two-Step Noncatalyzed Hydrolysis Mechanism of Imines at the Air-Water Interface.

The hydrolysis of imines has long been assumed to be their main atmospheric fate, based on early studies in the field of organic chemistry. However, the hydrolysis mechanism and kinetics of atmospheric imines remain unclear. Here, an advanced Born-Oppenheimer molecular dynamics method was employed to investigate the noncatalyzed hydrolysis mechanism and kinetics at the air-water interface by selecting CH2NH as a model molecule. The results indicate that CH2NH exhibits a pronounced surface preference. The noncatalyzed hydrolysis of CH2NH follows a unique two-step reaction mechanism involving first proton transfer and then OH- transfer through the water bridge at the air-water interface, in contrast to the traditional one-step mechanism. The calculated reaction rate for the rate-determining step is 3.32 × 105 s-1, which is 2 orders of magnitude greater than that of the bulk phase. In addition, the involvement of the interfacial electric field further enhances the reaction rate by approximately 3 orders of magnitude. The noncatalyzed hydrolysis rate at both the air-water interface and the bulk phase is higher than that of the possible acid-catalyzed one, clarifying noncatalyzed hydrolysis as the dominant mechanism for CH2NH. This study elucidates that the noncatalyzed hydrolysis of atmospheric imines is feasible at the air-water interface and that the revealed unique two-step hydrolysis mechanism has significant implications in atmospheric and water environmental chemistry.

Характеристика антиоксидантной активности СО2- экстрактов бурых водорослей и стабилизации липидов

Vegetable oils are susceptible to oxidation during storage, which is a serious problem for shelf-life and food safety. The article describes the antioxidant properties of supercritical extracts from brown algae (Undaria pinnatifida and Costaria costata), Russian Far East. It also explains their prospects as stabilizers that preserve the quality and safety of vegetable oils by affecting the kinetics of oxidation and hydrolysis. The study featured supercritical extracts of marine brown algae Undaria pinnatifida and Costaria costata from Russian Far East. The methods involved spectrophotometry and high-performance liquid chromatography. Supercritical extracts of marine brown algae proved to be reliable sources of bioactive substances, e.g., phenolic compounds, carotenoids, and mannitol. They also possessed antioxidant properties in terms of antiradical activity, hydroxyl ion binding, superoxide radical absorption, and Fe+2 chelating. The experiments revealed nine phenolic compounds responsible for antioxidant properties. The supercritical extract of Costaria costata demonstrated a greater antioxidant effect on lipid oxidation in vegetable oils than Undaria pinnatifida. Both algae proved effective in stabilizing hydrolysis and were able to increase the shelf-life of soy and sunflower oils by three months. Supercritical extracts of Undaria pinnatifida and Costaria costata served as antioxidants to stabilize lipid oxidation in refined and unrefined soy and sunflower oils. The research revealed high approximation coefficients for regression equations describing the patterns of changes in the peroxide and acid numbers of vegetable oils stabilized with supercritical extracts of these marine brown algae.

Improvement of the production of pequi almond (Caryocar brasiliense Camb.) protein hydrolysates through ultrasound-assisted enzymolysis: Impact on hydrolysis kinetics, structure and functional properties of hydrolysates

This study investigated the kinetics of ultrasound (US)-assisted hydrolysis of pequi almond protein (PAP) and the conformational and multifunctional characteristics of the hydrolysates. The US-assisted enzymolysis of PAP using Alcalase® was conducted in a US bath (25 kHz, 38 W/L) for 180 min at 60 °C and pH 7.5. The results showed an increase in the rate of proteolysis by 11.3 %, leading to a higher final degree of hydrolysis (25.2 %) and a greater concentration of TCA-soluble proteins after 45 min and 180 min (29 % and 8 %, respectively). Both conventional and US-assisted hydrolysis led to the breakdown of the protein structure, forming low molecular weight peptides (<15 kDa). However, US-assisted hydrolysis demonstrated greater fragmentation of the PAP surface, enhancing enzymatic efficacy. Intrinsic fluorescence and UV spectroscopy indicated increased exposure of hydrophobic groups throughout hydrolysis, and FTIR spectroscopy revealed changes in the amide bands, suggesting structural transitions in the protein. Finally, the hydrolysates obtained from the USassisted reaction showed higher solubility (≤27 % at pH 6.0), foaming capacity (≤82 % at pH 6.0), and antioxidant activity (≤40 %). Therefore, these results indicate the potential of the US to improve the performance of Alcalase® in the hydrolysis of PAP, producing compounds of industrial interest.

Impact of the stepwise implementation of INFOGEST semi-dynamic conditions on in vitro starch and protein digestion: A case study on lentil cotyledon cells

The impact of food design parameters on digestion is mostly studied using static in vitro digestion models. In this work, the complexity of the static model was gradually increased, by implementing several dynamic gastric reactor conditions, i.e., gradual (i) acidification, (ii) pepsin addition, and (iii) emptying, as well as (iv) saliva in the oral phase. As a relevant case study, starch and protein digestion was studied in lentil cotyledon cells under these conditions. Implementation of these dynamic parameters affected gastric proteolysis, linked to the pH-dependence of pepsin, and amylolysis, linked to the pH-dependence of salivary amylase activity. Though gastrointestinal hydrolysis kinetics were affected by the applied simulation conditions, similar levels of starch and protein digestion were generally reached at the end of the simulated digestion. Salivary amylase was not completely inactivated at the low gastric pH conditions, resulting in significantly higher levels of small intestinal starch digestion upon saliva inclusion. Gastric emptying significantly affected macronutrient hydrolysis kinetics. In that regard, an approach separately considering gastric samples taken upon different gastric emptying times should be preferred over the pooling of gastric samples before simulating small intestinal digestion.

White mulberry leaf (Morus alba L.) infusion as a strategy to reduce starch digestibility: The influence of particle size of leaf powder

Mulberry leaf (Morus Alba L.) has been found in clinical trials to be effective in reducing diabetes in Asia. The powdered tea market is expanding in popularity due to its functional properties. This study aimed to examine the influence of different particle sizes of mulberry leaf powder (MLP) infusion on the digestibility of starch in cooked Japonica rice (cv. Koshihikari) and the bioaccessibility of phytochemicals. Dried mulberry leaf was pulverized and sieved into several particle sizes: 160 μm (MLP160), 250 μm (MLP250), 404 μm (MLP404), and 774 μm (MLP774). Through simulated in vitro digestion, we assessed starch hydrolysis (%SH), the kinetics of starch hydrolysis, estimated glycemic index (eGI), as well as total phenolic content (TPC) and total flavonoid content (TFC). The smaller particle size of MLP showed a greater reduction of eGI. Specifically, infusions prepared from MLP160 resulted in a reduction of 15 % in eGI for cooked grains and 3 % for slurries, respectively. The reduction in eGI was attributed to the interaction among flavonoids and digestive enzymes, demonstrating a concentration-dependent manner on enzyme inhibition effect. Pulverization significantly influenced the concentration of phytochemicals and their bioaccessibility in infusions. This study offers valuable insights into determining optimal particle sizes for MLP, considering both physical and functional characteristics as well as implications for the food industry. The results further suggest that MLP infusion holds promise as a functional beverage, potentially providing benefits in reducing postprandial hyperglycemia.

Kinetics of Hydrolytic Depolymerization of Textile Waste Containing Polyester

Textile products comprise approximately 10% of the total global carbon footprint. Standard practice is to discard apparel textile waste after use, which pollutes the environment. There are professional collectors, charity organizations, and municipalities that collect used apparel and either resell or donate them. Non-reusable apparel is partially recycled, mainly through incineration or processed as solid waste during landfilling. More than 60 million tons of textiles are burnt or disposed of in landfills annually. The main aim of this paper is to model the heterogeneous kinetics of hydrolysis of multicomponent textile waste containing polyester (polyethylene terephthalate (PET) fibers), by using water without special catalytic agents or hazardous and costly chemicals. This study aims to contribute to the use of closed-loop technology in this field, which will reduce the associated negative environmental impact. The polyester part of waste is depolymerized into primary materials, namely monomers and intermediates. Reaction kinetic models are developed for two mechanisms: (i) the surface reaction rate controlling the hydrolysis and (ii) the penetrant in terms of the solid phase rate controlling the hydrolysis. A suitable kinetic model for mono- and multicomponent fibrous blends hydrolyzed in neutral and acidic conditions is chosen by using a regression approach. This approach can also be useful for the separation of cotton/polyester or wool/polyester blends in textile waste using the acid hydrolysis reaction, as well as the application of high pressure and the neutral hydrolysis of polyester to recover primary monomeric constituents.

Tuning the Stability and Kinetics of Dioxazaborocanes.

We investigated the equilibrium reaction of boronic acid (BA), diethanolamines (DEA), and 1,3,6,2-dioxazaborocanes (DOAB) in aqueous solutions, both theoretically and experimentally. Our findings show that the association constant can be adjusted by substituting BA and DEA derivatives, ranging from 100 to 103 M-1, exhibiting a bell-shaped pH dependency. The highest stability was achieved when the pKa values of DEA and BA were closely matched. This approach enabled the preparation of a highly stable DOAB under physiological conditions. Furthermore, the hydrolysis kinetics of DOABs were controllable over a range of five orders of magnitude based on the substituent's steric effect. In the slowest case, this resulted in quasi-static stability with only 1% cleavage in the first hour, followed by a week-long cleavage period to reach equilibrium. These insights could establish a unique chemistry platform for designing scheduled cleavability on a day-to-week timescale, relevant to protein engineering, immunotherapy, and other smart drug delivery applications.

Particle Size Effect on Anaerobic Digestion of Fruit and Vegetable Waste

During the anaerobic digestion (AD) of fruit and vegetable waste (FVW), excessive particle size reduction can lead to the overproduction and inhibition of methanogenic microorganisms. This paper presents an in-depth analysis through experimental assays, modeling, and response surface analysis of the effect of particle size on methane production. A simple model was proposed considering the inhibition of the growth of methanogenic microorganisms and surface-based hydrolysis kinetics. The model parameters were estimated using experimental data from batch systems fed with FVW of varying particle sizes (ranging from 1.8 to 1000 μm). Response surface methodology establishes a statistical model for estimating methane production based on particle size and concentration. Numerical and statistical analyses were conducted using Matlab R2024a and Minitab 24 software. A model with an R2 of 0.89 was obtained, which determined an optimal concentration of 8.2 kg·m−3 and a particle size of 742.3 μm, yielding a methane production of 303.3 m3·kg−1 VS, similar to the experimentally obtained range of 300.95 to 316.7 m3·kg−1 VS.

Microstructure and improved hydrogen generation performance via hydrolysis of Mg–Ca alloys with TiC and Ni addition

Mg-xCa (x = 3, 7, 11, 14, wt.%) binary hypoeutectic alloys are successfully synthesized via solidification in the present work. The microstructure, phase compositions and hydrogen generation characteristics of as-cast Mg–Ca alloys and ball milled Mg–Ca composites with TiC and Ni addition have been investigated in this work for a new hydrogen supply source application. A lamellar structure with alternately distributed Mg and Mg2Ca is formed in the eutectic regions of as-cast Mg–Ca binary alloys. It is found that as-cast Mg–Ca binary alloys show extremely sluggish hydrolysis kinetics and low hydrogen yield in both tap water and simulated seawater. Mg2Ca phase preferentially reacts with water during hydrolysis process in simulated seawater. Many cracks arise with hydrolysis reaction, meanwhile, the cracks further assist in the hydrolysis of the internal matrix via assisting water solution transfer. After ball milling with TiC and Ni of Mg–Ca binary alloys, the hydrolysis performance is substantially modified. Mg–14Ca-3wt.%TiC-5wt.%Ni composite generates 836.6 mL g−1 of hydrogen within initial 95 min. The conversion rate of Mg–14Ca-3wt.%TiC-5wt.%Ni composite in simulated seawater is as high as 99.4%, indicating a thorough hydrolysis of Mg and Mg2Ca phases with the catalysis of TiC and Ni. This work shows that microstructure refinement, catalysis, Mg(OH)2 exfoliation and water solution transfer account for the complete hydrolysis.

Enhanced hydrolysis of spiramycin in aqueous solution using SiO2/SO3H

Abstract Sulfonated silicon dioxide (SiO2/SO3H) solid acids were synthesized and they were characterized and used for spiramycin hydrolysis pretreatment of antibiotic wastewater. Results show that the spiramycin removal effect rankings are as follows: SiO2/SO3H &gt; SiO2 (pH = 3 or so) &gt; control group. A first-order model was used to reflect the hydrolytic kinetics. The hydrolysis rate of the SiO2/SO3H solid acid calcined at 600°C is the highest, up to 3.59×10−2 (k). The performance of SiO2/SO3H is in positive correlation with the total acidity, which was determined by using the n-butylamine titration method. This hydrolytic method eliminates the need for the on-site handling of hazardous and corrosive mineral acids. As an attractive selective catalytic pretreatment method, it is targeted at removing related functional groups from antibiotics to reduce the inhibitory effect and allow antibiotic wastewater to further be easily biologically treated.

Delignification and enzymatic hydrolysis kinetics of KOH microwave-assisted pretreated banana stem for bioethanol production

Biomass pretreatment is essential to facilitate lignin removal and enhance cellulose concentration for optimal bioethanol production. Therefore, this research aimed to determine the effects of conventional KOH (KP) and Combined KOH microwave-assisted (CKMP) pretreatment on the banana stem (BS) composition, analyzing the kinetics of lignin removal at various temperatures and KOH concentrations for 25 min. Kinetics variables were calculated by fitting experimental data and cellulose was hydrolyzed to produce reducing sugars. The results showed that the highest lignin removal for KP and CKMP were 37.11%, and 40.39%, respectively, with CKMP having the lowest activation energy of approximately 2.688 kJ mol−1. CMCase and FPase activity were 1988.3474 and 1605.4187 U mL−1, respectively, which were significantly higher than the values reported in previous research. The maximum concentration of reducing sugars achieved was 17.69 g L-1, with an enzyme concentration of 50% (v/w), pH 5, and a hydrolysis duration of 25 h. Michaelis constant varied from 0.0037 to 0.0079, and the maximal rate ranged from 1.28 × 10−6 to 2.76 × 10−6 Mol L−1 s−1 when computing the reaction rate using the Michaelis–Menten kinetics model.

Interfacial Coating of Graphene Nanosheets to Control the Hydrolysis Kinetics of LiAlH4 at Subzero Temperatures

Interfacial Coating of Graphene Nanosheets to Control the Hydrolysis Kinetics of LiAlH₄ at Subzero Temperatures

Carbon nano-tube coated with iron carbide catalysis for hydrolysis of magnesium to generate hydrogen

Hydrolysis of magnesium (Mg) or their composites are considered as an efficient, economical and enabling technique to produce hydrogen (H2). In this study, carbon nano-tube coated with iron carbide (CNT@Fe3C) was synthesized and applied as a catalyst to promote hydrolysis of Mg to generate H2. Ball milling technique was employed to prepare Mg-Xwt%CNT@Fe3C (X = 0.2, 2.0, 5.0 and 10.0) composites for hydrolysis in seawater. Among employed composites, the results demonstrated that the introduction of small amount of CNT@Fe3C promote the hydrolysis kinetics of Mg. Particularly, Mg-5.0 wt%CNT@Fe3C composite ball milled for 1 h released 866.5 mL/g H2 with 10072.0 mLg−1min−1 initial hydrogen generation rate mHGR and demonstrated an excellent composite. Furthermore, activation energy of Mg hydrolysis kinetic dropped to 23.6 kJ/mol. Hence, CNT@Fe3C inhibited the magnesium hydroxide (Mg(OH)2) from sticking to the unreacted Mg surfaces, which enhanced its galvanic corrosion and reactivity. In order to develop portable H2 generators, CNT@Fe3C supported Mg system can provide clean H2 to reduce the adverse environmental effect.

Hydrolysis kinetics of self-degradable diverters for well stimulation

Self-degradable diverters have gained increased popularity in well stimulation as an environmentally friendly and robust fluid diversion technology. As of now, limited data and conflicting information exist in the literature regarding the hydrolytic degradation rates of diverters under field-representative conditions, and knowing these rates is crucial for optimizing well stimulation designs. In this work, we systematically measured the degradation rates of commercial self-degradable diverters in aqueous solutions spanning a wide solution pH range of 0.3–13.6 and a wide temperature range of 60–110 °C. We first demonstrated that existing bottle degradation test protocols might return misleading results due to the alteration of solution pH by degradation products, and we developed a more reliable experimental protocol using buffer solutions instead. Using this procedure, we found that as the solution pH increased, the hydrolysis rate of diverters first decreased and then increased, with a minimal degradation rate at around pH = 4. Elevated temperatures yielded faster hydrolysis. The collected kinetic data fit reasonably well to a published kinetic model that was originally developed for pure polylactic acid in deionized water, with an R2 value over 0.98 for all pH and temperature conditions. This comparison suggests that the model can be more widely applied to describe the degradation kinetics of commercial diverters over broad temperature and pH ranges. The test protocol, experimental data, and kinetic analysis in this work provide important guidance on improving the efficiency of fluid diversion and well stimulation operations.

Ultrasound-assisted hydrolysis of food waste using glucoamylase: Statistical optimization and mechanistic analysis with molecular simulations

This paper reports investigations in food waste hydrolysis using ternary approach that combines statistical optimization, ultrasound-assisted enhancement of hydrolysis kinetics, and molecular simulations that provide physical insight into the process. Initial optimization of hydrolysis parameters (Box–Behnken design) resulted in total reducing sugar yield of 263.4 mg/g biomass in 42 h. Sonication of hydrolysis mixture at 35 kHz at 20 % duty cycle yielded 4× reduction in hydrolysis time with 22 % enhancement in TRS yield (320 mg/g biomass). Analysis of GLCM's secondary structure through FTIR spectra deconvolution revealed significant changes induced by sonication. Sonication led to reduction in α-helix, and increase in random coil content. Molecular dynamics simulations unveiled majority of amino acid residues associated with GLCM binding pocket in α-helix and random coil regions. Consequently, sonication widened the binding pockets, facilitating easier transport of substrate and product. This effect translated into faster kinetics of enzymatic food waste hydrolysis.

Effective Ethyl Carbamate Prevention in Red Wines by Treatment with Immobilized Acid Urease.

Climate change poses several challenges in the wine industry, including increasing risks related to chemical food contaminants such as biogenic amines and ethyl carbamate (EC). In this work, we focused on urea removal in red wines by immobilized acid urease aiming at limiting EC formation during wine storage. By considering separable kinetics of catalyst deactivation and urea hydrolysis, it was possible to model the time course of urea removal in repeated uses in stirred batch reactors. Treatments based on immobilized urease of red wine enriched with 30 mg/L of urea allowed the reduction in the contaminant concentration to <5 mg/L. After 28.5 h of treatment, the observed urea level was reduced to about 0.5 mg/L, corresponding to a decrease in the potential ethyl carbamate (PEC) from 1662 μg/L to 93 μg/L, below the level of the non-enriched wine (187 μg/L). As a comparison, when treating the same wine with the free enzyme at maximum doses allowed by the EU law, urea and PEC levels decreased to only 12 mg/L and 415 μg/L respectively, after 600 h of treatment. These results show that, for red wines, urease immobilization is an effective strategy for urea removal and, thus, effective reduction in ethyl carbamate as a process contaminant. This study provides the scientific background for the future scaling-up of the process at an industrial level.