Ultrasonic analysis of kinetic mechanism of hydrolysis of cellobiose by β-glucosidase

Ultrasonic Characterisation of W/O Microemulsions - Structure, Phase Diagrams, State of Water in Nano-Droplets, Encapsulated Proteins, Enzymes

“…Enzyme concentrations were determined by weight as a mass of liquid preparation (Novozyme 188 L (Novo Nordisk A/S); β-glucosidase preparation was obtained from Aspergillus niger microorganisms, with a declared minimum activity of 250 CbU per gram of liquid). Amount of protein in the preparation and other details of its composition were described earlier (Resa & Buckin, 2011). Enzyme was added to the substrate (cellobiose) solution (or emulsion) at room temperature and thoroughly mixed for 30 s, then degassed and loaded into the measuring cell of HR-US 102 differential ultrasonic spectrometer (Sonas Technologies Lt.) equilibrated at 25.0 o C. The concentration of enzyme preparation in aqueous phase was 0.87 mg/mL.…”

“…The capability of this and other ultrasonic techniques were demonstrated for a variety of reactions catalysed by enzymes, namely, urease, -amylase and catalase (Kudryashov et. al, 2003), chymosin (Dwyer et al, 2005) proteinase K (Buckin & Craig, 2005), invertase (Resa et al, 2009), and cellobiase (Resa & Buckin, 2011) as well as other types of bioprocesses (McClements, 1995;Povey, 1997). It provided the detailed reaction extent and rate profiles in a broad range of concentrations, allowed analysis of the reverse reaction, determination of equilibrium constant and of the molar Gibbs free energy of reactions as well as analysis of reactions kinetic models (Resa & Buckin, 2011).…”

“…al, 2003), chymosin (Dwyer et al, 2005) proteinase K (Buckin & Craig, 2005), invertase (Resa et al, 2009), and cellobiase (Resa & Buckin, 2011) as well as other types of bioprocesses (McClements, 1995;Povey, 1997). It provided the detailed reaction extent and rate profiles in a broad range of concentrations, allowed analysis of the reverse reaction, determination of equilibrium constant and of the molar Gibbs free energy of reactions as well as analysis of reactions kinetic models (Resa & Buckin, 2011). Figure 4(b) illustrates our results for the real-time ultrasonic monitoring of activity enzyme, β-glucosidase, in aqueous solution (10 mM sodium acetate buffer, pH 4.90) and encapsulated in IPM microemulsion (50:50 w/w ratio of oil to surfactant+cosurfactant) at 24% water in the presence of substrate, cellobiose (disaccharide).…”

“…, where M represents the molar mass of a particular component and symbols G , W and C stand for glucose, water and cellbiose (Resa & Buckin, 2011). The value of uW a is the concentration increment of ultrasonic velocity of water added to microemulsion in the amount consumed by the reaction.…”

Ultrasonic Monitoring of Biocatalysis in Solutions and Complex Dispersions

“…The presence of the parameter u 0 in Equations (3)-(6) provides direct relationships linking a R and a P with apparent compressibility and volume of the reactants and products (see for example Reference [13]). 'Libraries' of these properties can be used for estimations of a R , a P and ∆a r (see Discussion in [25] as example). Although the concentration c(t) can be expressed in different units, such as molarity or molality, it is useful to use moles per kg of mixture.…”