Improvement of pectinase, xylanase and cellulase activities by ultrasound: Effects on enzymes and substrates, kinetics and thermodynamic parameters

摘要

Ultrasound effects were investigated on pectinase (PE), xylanase (XLN) and cellulase (CE) activities at different pH, temperatures, and by sonication pre-treatment, comparing the reaction at ultrasound bath (US) and at a mechanical stirring (MS). In general, US increased the activity of the enzymes by 5% for PE, 30% for XLN and 25% for CE compared to MS. US provided a higher activity at extremes pH (pH 3 and 7), mainly for XLN and CE. The substrate and enzyme pre-sonication enhanced the activities. The previous sonication of xylan increased the xylanase activity in almost 30% under US and almost 20% under MS. On the other hand, cellulase pre-sonication increased the activity in 50% under US and 40% under MS. The catalytic efficiency (V-max/K-M) increase 25% for PE and 17% for higher XLN and CE under US. US affected the PE activity at low temperature improving 10% the PE activity, while its effect was more representative at high temperatures, where the enzymatic activities of XLN and CE were 33% and 15% higher. Our results demonstrated that ultrasound can affect enzymes and substrates, making it a powerful tool for enzymatic-catalyzed reactions.