Modified chitosan microspheres in non-aggregated amylase immobilization (original) (raw)
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Bioprocess and biosystems engineering, 2018
Maltose syrups have got wide-range utilizations in a variety of applications from bakery to drug-development. α-Amylases are among the most widely utilized industrial enzymes due to their high specificity in production of maltose syrup from starch. However, enzymes are not stable in ex vivo conditions towards alteration in pH, temperature, and such other parameters as high salt concentrations and impurities, where immobilization is required to advance the stability of the enzyme with which approach the requirement of isolation of the enzyme from media is eliminated as well. In this study, Termamylα-amylase was immobilized on the none-modified chitosan beads (NMCB), L-lysine-modified chitosan beads (LMCB), and L-asparagine-modified chitosan beads (AMCB) to assess effects of the support material on optimum conditions and kinetic parameters of the α-amylase activity in production of maltose from starch. Immobilization on NMCB, LMCB, and AMCB puts a strong influence on optimum pH, optim...
Preparation of chitosan particles suitable for enzyme immobilization
Journal of Biochemical and Biophysical Methods, 2008
Macro-, micro-and nanosized chitosan particles suitable as immobilization carriers were prepared by precipitation, emulsion cross-linking and ionic gelation methods, respectively. Effects of particle preparation parameters on particle size were investigated. Activities of β-galactosidase covalently attached to differently sized particles have been evaluated and compared. The highest activity was shown by the biocatalyst immobilized on nanoparticles obtained by means of the ionotropic gelation method with sodium sulphate as gelation agent. β-Galactosidase fixed on macro-and microspheres exhibited excellent storage stability in aqueous solution, with no more than 5% loss of activity after 3 weeks storage at 4°C and pH 7.0.
Food chemistry, 2015
A Box-Behnken design of Response Surface Methodology (RSM) was utilised for optimisation of parameters affecting immobilisation of Fenugreek β-amylase on chitosan coated PVC (polyvinyl chloride) beads and beads made from chitosan/PVP (polyvinylpyrrolidone) blend, which resulted in 85.2% and 81% immobilisation efficiency, respectively. Immobilisation resulted in shift of pH optima while the optimum temperature remained unaffected. Enhancement in thermal stability of the enzyme was observed on conjugation with both the matrices. The immobilised enzyme appeared suitable for industrial applications due to the non-toxic nature of chosen matrices, ease of immobilisation procedure, enhanced stability and reusability with retention of 72% and 60% residual activity after 10 uses for the enzyme immobilised on chitosan coated PVC beads and on the beads of chitosan/PVP blend, respectively.
Starch-Starke, 2014
Immobilization of a-amylase onto bentonite/chitosan (BC) composite was studied via adsorption. The composite was characterized by FTIR, SEM, and surface area measurements. The effect of different factors such as, pH, temperature, initial enzyme concentration, and various thermodynamic parameters was determined. The maximum a-amylase adsorption capacity of the BC composite was determined as 64 mg/g at 0.8 mg/mL enzyme concentration. The activity of the immobilized enzyme was measured under varying experimental conditions. The highest enzyme activity for free and immobilized enzyme was determined at 30 and 35°C in 0.1 M phosphate buffer at pH 7.0. The effect of substrate concentration on enzyme activity of free and immobilized enzymes showed a good fit to the Lineweaver-Burk plots. Michaelis constant, K m , for the immobilized a-amylase was found to be higher than for the free enzyme. The adsorption isotherm was modeled by the Langmuir equation.
Stability of α-amylase immobilized on poly(methyl methacrylate-acrylic acid) microspheres
Journal of Biotechnology, 1998
Poly(methyl methacrylate-acrylic acid) microspheres were prepared and the acid groups were activated by using either carbodiimide (CDI) or thionyl chloride (SOCl 2 ). h-Amylase was covalently bound on these activated microspheres. The properties of the immobilized enzyme were investigated and compared with those of the free enzyme. The relative activities were found to be 80.4 and 67.5% for carbodiimide and thionyl chloride bound enzymes, respectively. Maximum activities were obtained at lower pHs and higher temperatures upon immobilization compared to free enzyme. No change in V max and approximately 12-fold increase in K m were observed for immobilized enzymes. The enzyme activities, after storage for 1 month, were found to be 24.5 and 52.5% of the initial activity values for CDI and SOCl 2 activated matrices, respectively. On the other hand the free enzyme lost its activity completely in 20 days. Immobilization, storage stability and repeated use capability experiments carried out in the presence of Ca 2 + ions demonstrated higher stability, such as SOCl 2 immobilized enzyme retained 83.7% and CDI immobilized enzyme retained 90.3% of the original activity of the enzyme. The immobilized enzymes that were used 20 times in 3 days in repeated batch experiments demonstrated that, in the absence of Ca 2 + ions about 75% and in the presence of Ca 2 + ions greater than 90% of the original enzyme activity was retained.
Mediterranean Journal of Chemistry, 2020
In this research, the immobilization of α-amylase from Bacillus subtilis ITBCCB148 by crosslinking method on chitosan matrix has been performed. This research aims to know the effect of immobilization on the thermal stability of α-amylase. The results showed that the native α-amylase has an optimum temperature of 65 o C, KM = 1.6 mg mL-1 substrate, and Vmax = 39.7 µmol mL-1 min-1. The immobilized α-amylase has optimum temperature of 75 o C, KM = 3.5 mg mL-1 substrate, and Vmax = 7.05 µmol mL-1 min-1. The residual activity of the native and immobilized enzyme on thermal stability test at 65 o C for 80 minutes was 58% and 86.15%, respectively. The immobilized enzyme can be reused up to six repeated cycles.The thermodynamic data of native enzyme was t½ = 113.6 min, ki = 6.1x10-3 min-1 , and ΔGi = 107.3 kJ mol-1 , while the immobilized enzyme was t½ = 433.1 min, ki= 1.6x10-3 min-1 , and ΔGi 111.1 kJ mol-1. Based on the decrease of ki, and the increase of ΔGi and half-life(t½) values, the immobilization of α-amylase with chitosan can increase the thermal stability of this enzyme.
Mediterranean Journal of Chemistry, 2020
In this research, the immobilization of α-amylase from Bacillus subtilis ITBCCB148 by crosslinking method on chitosan matrix has been performed. This research aims to know the effect of immobilization on the thermal stability of α-amylase. The results showed that the native α-amylase has an optimum temperature of 65 o C, KM = 1.6 mg mL-1 substrate, and Vmax = 39.7 µmol mL-1 min-1. The immobilized α-amylase has optimum temperature of 75 o C, KM = 3.5 mg mL-1 substrate, and Vmax = 7.05 µmol mL-1 min-1. The residual activity of the native and immobilized enzyme on thermal stability test at 65 o C for 80 minutes was 58% and 86.15%, respectively. The immobilized enzyme can be reused up to six repeated cycles.The thermodynamic data of native enzyme was t½ = 113.6 min, ki = 6.1x10-3 min-1 , and ΔGi = 107.3 kJ mol-1 , while the immobilized enzyme was t½ = 433.1 min, ki= 1.6x10-3 min-1 , and ΔGi 111.1 kJ mol-1. Based on the decrease of ki, and the increase of ΔGi and half-life(t½) values, the immobilization of α-amylase with chitosan can increase the thermal stability of this enzyme.
Food Chemistry, 2016
The immobilization of maltogenic a-amylase from Bacillus stearothermophilus (BsMa) onto novel porous poly(urethane urea) (PUU) microparticles synthesized from poly(vinyl alcohol) and isophorone diisocyanate was performed by covalent attachment to free isocyanate groups from PUU microparticles, or by physical adsorption of enzyme onto the surface of the carrier. The influence of structure, surface area and porosity of microparticles on the catalytic properties of immobilized BsMa was evaluated. The highest efficiency of immobilization of BsMa was found to be 72%. Optimal activity of immobilized BsMa was found to have increased by 10°C compared with the native enzyme. Influence of concentration of sodium chloride on activity of immobilized BsMa was evaluated. High storage and thermal stability and reusability for starch hydrolysis of immobilized enzyme were obtained. Immobilized BsMa has a great potential for biotechnology.