Improvement of thermostability and activity of pectate lyase in the presence of hydroxyapatite nanoparticles.

The activity and half-life of pectate lyase (PL) from Bacillus megaterium were nine- and 60-fold, respectively, higher at 90 °C in the presence of hydroxyapatite nanoparticles (NP-PLs) than in the presence of 1mM CaCl(2). Thermodynamic analysis of the nanoparticle-induced stability revealed an enhanced entropy-enthalpy compensation by the NP-PLs since a reciprocal linearity of the enthalpy-entropy change to 90 °C was observed. Without nanoparticles, the linearity range was 70 °C. Such compensation reflected the maintenance of the native structure of proteins. The remarkable enhancement of activity and stability of the NP-PL system at high temperatures may be utilized commercially e.g. in the food industry or the processing of natural fibers that may require a thermotolerant enzyme.