Impact Of Ultrasonic Treatment Research Articles

Effect of ultrasonic treatment on enzymes: Decoupling the relation between the ultrasonic driven conformational change and enzyme activity

Considering the growing interest in enzyme-based extraction technology as a safe and eco-friendly extraction technique, along with the relatively high cost associated with enzymatic applications, it became necessary to explore novel strategies aimed to improve enzyme activity. In this study, the impact of ultrasonic treatment on commercial cellulase and pectinase was investigated. As this effect may be influenced by various ultrasonic and enzyme-related parameters, changes in enzyme conformation were explored under optimal and non-optimal enzyme conditions. The intrinsic fluorescence spectrum was utilized as a tool for monitoring these changes. Additionally, the enzyme’s catalytic potential was also assessed under the same conditions. Results indicated that the impact of ultrasonic treatment on enzyme conformation primarily depends on the total ultrasonic energy delivered to the system, rather than other ultrasonic parameters such as power, sample volume, treatment time, or duty cycle. The maximum relative decrease in intrinsic fluorescence intensity of Pectinex® Ultra Clear (PUC) and Pectinex® Ultra SPL (PUS) after ultrasonic treatment was approximately 51% and 55%, respectively, while the decrease induced by thermal denaturation was 25% and 30% respectively. Furthermore, a blue shift in the fluorescence spectrum of both pectinases was observed upon sonication for all process conditions indicating a change in enzyme conformation. However, ultrasonic treatment did not result in a significant change in enzyme activity, suggesting that these conformational adjustments may occur in regions other than the active sites. Moreover, ultrasonicated pectinases and cellulases did not exhibit any improvement in their catalytic potential under either optimal or non-optimal conditions.

QuEChERS Extraction of PAHs from Various Soils and Sediments Followed by Chromatographic Determination

We studied the features of PAHs extraction by QuEChERS in the sample preparation of soils and bottom sediments of various compositions followed their determination by gas chromatography–mass-spectrometry. The test samples were soils of sandy, loamy sand, loamy, and clayey types and bottom sediments of loamy sand type. The mineralogical composition and organic matter content of the samples were used to predict how PAHs were retained by the soils and sediments. The impact of ultrasonic treatment on analyte extraction with subsequent identification by chromatography was assessed. No ultrasonic treatment was required to extract and determine all PAHs (up to 100%) in sandy and loamy sand soils and low-molecular-weight PAHs in all test samples. The QuEChERS extraction and determination of high-molecular-weight PAHs in clay type soil samples and loamy sand bottom sediments required a 10-min ultrasonic treatment, while the recoveries of analytes were higher than 87 and 90%, respectively. The analysis of a loamy soil sample with a high organic matter content was the most challenging. To extract over 70% of high-molecular-weight PAHs from a sample of this type using the QuEChERS technique, the binary acetonitrile–acetone (1 : 1) extractant rather than conventional acetonitrile was used with the simultaneous 15-min ultrasonic treatment.

Ultrasonic suppression of element segregation in gas tungsten arc cladding AlCoCuFeNi high-entropy alloy coatings

The excellent mechanical and corrosion properties make high-entropy alloys (HEA) be promising structural and coating materials. However, problems like element segregation hinder the fabrication and application of HEA. Ultrasonic melt treatment (USMT) generally has the effect of segregation suppression. In the present study, the impact of ultrasonic treatment on the microstructure, segregation, mechanical properties, and corrosion properties of AlCoCuFeNi HEA coatings prepared by gas tungsten arc (GTA) cladding on low-carbon substrates are examined and discussed. It was found that the coatings with and without ultrasonic treatment both have BCC dendrites and FCC interdendrites. Ultrasonic treatment increases phase fraction of BCC and narrow secondary dendrite arm spacing (SDAS), thereby increasing hardness, elastic modulus, and room-temperature creep resistance. Ultrasonic treatment suppresses dendritic segregation, thereby improving corrosion properties in 3.5 wt% NaCl solution. According to analysis, acoustic streaming has a greater impact compared with cavitation, which accelerates flow velocity and increases the cooling rate. This study preliminarily examines the effectiveness of ultrasonic treatment in suppressing segregation in HEA. • AlCoCuFeNi high-entropy alloy coatings are prepared by ultrasonic assisted gas tungsten arc cladding. • Ultrasonic increases the phase fraction of BCC and refines microstructure. • Ultrasonic increase microhardness and improve corrosion performance.

Ultrasonic treatment at different pH values affects the macromolecular, structural, and rheological characteristics of citrus pectin

Ultrasonic degradation has become a promising strategy for producing modified pectin (MP). In this study, the impact of ultrasonic treatment at various pH values (4.0, 7.0, and 10.0) on the macromolecular, structural and rheological characteristics of citrus pectin was investigated. Results demonstrated that ultrasonic irradiation at the higher pH led to larger reductions in the intrinsic viscosity and weight-average molecular weight of pectin. The degradation kinetics of pectin at different pH values under ultrasound well fitted to a second-order reaction kinetics model. Acoustic cavitation, β-elimination, and demethylation led to the breakage of glycosidic linkages of side chains and methoxyl groups of pectin, but did not have noticeable influences on the main chain of pectin. The ultrasonic treatment at a high pH led to an apparent change in the rheological characteristics of pectin. Therefore, ultrasonic treatment at various pH values can be developed as a viable means to prepare desirable MP.

The impact of ultrasonic treatment on blueberry wine anthocyanin color and its In-vitro anti-oxidant capacity

Ultrasound (US) has been recognized as a non-thermal technology for accelerating blueberry wine aging for flavor development. However, influence of US on anthocyanin and color characteristics is uncertain. In this study, US was applied to new blueberry wine, and changes in color characteristics, anthocyanin content and anti-oxidant capacity were evaluated at early stage of aging period. Low-frequency power US resulted in an improvement in color characteristics and lower chromatic aberration as compared to untreated samples, specially at condition of 180 W, 20 min and 2 cycles. Furthermore, this contribution was attributed to unattenuated anthocyanins protected from US stress. Importantly, the structural polarity dependence was mediated by the impact of US on anthocyanins. Additionally, anti-oxidant activity of blueberry wine was not adversely affected under a moderate US condition. US treatment of blueberry wine was therefore considered to significantly enhance the color presentation, hinting at the possibility of promoting blueberry wine aging.

The impact of ultrasonic treatment on activity of ammonia-oxidizing bacteria and nitrite-oxidizing bacteria in activated sludge

The ultrasonic treatment of sludge has been considered as an effective method to facilitate the partial nitritation of municipal sewage. This study aims to reveal the effects of ultrasound on ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB). The impact factors including ultrasonic irradiation time and intensity, sludge concentration, thermal effect and released free radicals were studied. The maximized difference between the changes in AOB and NOB activities were obtained with 10 g mixed liquor suspended solids (MLSS)/L, using 0.9 kJ/mL ultrasonic energy density and 12 h interval time. The increased ultrasonic intensity destroyed the floc structure of activated sludge, increased the microbial death, and decreased the cellular ATP level. Further, the mechanism exploration indicated that the mechanical shearing could be a critical factor in achieving the nitritation with inhibitory effect on nitrite oxidation.

Impact of ultrasonic treatment on dewaterability of sludge during Fenton oxidation.

Fenton oxidation was compared with Fenton oxidation coupled with ultrasonication (Fenton + US) for sludge dewatering. Different Fenton reagent (H2O2, Fe(2+)) concentrations, pH, and reaction times were studied in different systems on the basis of the specific resistance to filtration (SRF) and capillary suction time (CST). It was found that Fenton + US can significantly reduce Fe(2+) and H2O2 dosages and reaction times. After ultrasonication of the system at pH3, with an ultrasonic frequency of 25kHz and a sound energy density of 100W/L, the Fe(2+), H2O2 dosage, and reaction time were reduced by 66.7, 75.0, and 75.0%, respectively, when compared with Fenton oxidation at the same dewaterability of sludge. The microstructure of sludge and hydroxyl radical (·OH) density in Fenton oxidation and Fenton + US was further examined. Fenton + US produced more · OH in a sludge system than did individual Fenton oxidation. The concentration of · OH in Fenton + US fell from 79.2 to 6mg/L over 3.5h, while the concentration of · OH in Fenton oxidation fell from 59.6 to 1mg/L over 2h, thus destroying the microstructure of sludge more effectively. Sludge treated using Fenton + US for 30min showed a much thinner and looser microstructure.

Impact of ultrasonic treatment on properties of starch film-forming dispersion and the resulting films

Abstract In this study, power high intensity ultrasound was used to treat the gelatinized maize starch dispersions. To investigate the effects of ultrasound treatment on the properties of the film-forming dispersions and their resulting films, the apparent viscosity, solubility, morphology of the film-forming dispersions and the opacity, water vapor permeability, mechanical properties, X-ray diffraction of the films formed from these dispersions were tested. It was found that gelatinized maize starch dispersions treated by ultrasound for a certain period of time has a drastic decrease in viscosity, and a distinct increase in solubility. Microscopic observation shows distinctly rapture of ghost fragments in the dispersion with prolonged treatment time. It was also found that ultrasound treatment produces an excellent film with good transparency, improved moisture resistance and stronger structure.