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The thermodynamics and kinetics of traditional and simultaneous dual frequency energy-gathered ultrasound (SDFU) assisted enzymolysis of potato protein were investigated to get the knowledge of the mechanisms on the SDFU's promoting efficiency during enzymolysis. The concentration of potato protein hydrolysate and parameters of thermodynamic and kinetic during traditional and SDFU assisted enzymolysis were determined. The results showed that potato protein hydrolysate concentration of SDFU assisted enzymolysis was higher than traditional enzymolysis at the hydrolysis time of 60min (p<0.05) whereas not significantly different at 120min (p>0.05). In some cases, SDFU assisted enzymolysis took less hydrolysis time than traditional enzymolysis when the similar conversion rates of potato protein were obtained. The thermodynamic papameters including the energy of activation (E), enthalpy of activation (△H), entropy of activation (△S) were reduced by ultrasound pretreatment while Gibbs free energy of activation (△G) increased little (1.6%). Also, kinetic papameters including Michaelis constant (K) and catalytic rate constant (k) decreased by ultrasound pretreatment. On the contrary, reaction rate constants (k) of SDFU assisted enzymolysis were higher than that of traditional enzymolysis (p<0.05). It was indicated that the efficiency of SDFU assisted enzymolysis was higher than traditional enzymolysis in a limited time. The higher efficiency of SDFU assisted enzymolysis was related with the decrease of E and K by lowering the energy barrier between ground and active state and increasing affinity between substrate and enzyme.

The effect of ultrasound pretreatment using Single Frequency Counter Current Ultrasound (SFCCU) on the enzymolysis of tea residue protein (TRP) extracted with sodium hydroxide was investigated. The concentration of TRP hydrolysate, enzymolysis kinetics and thermodynamic parameters after SFCCU pretreatment were determined and compared with traditional enzymolysis. The results indicated that both ultrasound assisted and traditional enzymolysis conformed to first-order kinetics within the limits of the studied parameters. Temperature and sonication had affirmative effect on the enzymolysis of TRP with temperature yielding greater impact. Michaelis constant ( ) in ultrasonic pretreated enzymolysis decreased by 32.7% over the traditional enzymolysis. The highest polypeptide concentration of 24.12 mg ml was obtained with the lowest energy requirement at improved conditions of 50 g L of TRP, alcalase concentration of 2000 U g, time of 10 min and temperature of 50 °C for the ultrasonic treated enzymolysis. The values of reaction rate constant () for TRP enzymolysis increased by 78, 40, 82 and 60% at 20, 30, 40 and 50 °C, respectively. The thermodynamic properties comprising activation energy (), change in enthalpy ) and entropy) were reduced by ultrasound pretreatment whereas Gibbs free energy ) was increased.

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A polysaccharide of Irpex lacteus, a white‐rot fungus with lignocellulose‐degrading activities, has been used as a commercial medicine for nephritis treatment. Previously, a low‐intensity electromagnetic field (LI‐EMF) was found to increase the biomass and polysaccharide content of Irpex lacteus and induce twists on the cell surface. In this study, RNA‐sequencing (RNA‐seq) technology was used to analyze the underlying mechanism of LI‐EMF's influence on Irpex lacteus. We identified 3268, 1377, and 941 differentially expressed genes (DEGs) in the LI‐EMF‐treated samples at recovery times of 0 h, 3 h, and 6 h, respectively, indicating a significant decline in the influence of the LI‐EMF treatment on Irpex lacteus with the passage of recovery time. Moreover, 30 upregulated and 14 downregulated DEGs overlapped in the LI‐EMF‐treated samples at the recovery times of 0 h, 3 h, and 6 h, implying the important lasting effects of LI‐EMF. The reliability of the RNA‐seq data were validated by quantitative real‐time PCR (qRT‐PCR). The DEGs related to transcription factors, cell proliferation, cell wall, membrane components, amino acid biosynthesis and metabolism, and polysaccharide biosynthesis and metabolism were significantly enriched in the LI‐EMF‐treated samples. The experiments confirmed that the LI‐EMF treatment significantly increased the content of amino acids with a considerable increase in the content of essential amino acids. Therefore, the global gene expression changes explained the pleiotropic effects of Irpex lacteus induced by the LI‐EMF treatment. These findings provide the requisite data for the appropriate design and application of LI‐EMF in the fermentation of microorganisms to increase production. Bioelectromagnetics. 40:104–117, 2019. © 2019 Bioelectromagnetics Society