Inactivation of Heat-Resistant Lipase and Protease from Pseudomonas fluorescens by Manothermosonication

Abstract

The resistance of extracellular lipase and protease from Pseudomonas fluorescens to heat treatment and manothermosonication, a simultaneous application of heat and ultrasound under moderate pressure, were compared within a temperature range of 110 to 140°C. Manothermosonication inactivates both enzymes more efficiently than does heat treatment. Because temperature dependence of enzyme inactivation is different for manothermosonication and simple heat treatment, manothermosonication efficiency diminishes as temperature increases, but this loss of efficiency during UHT can be partially overcome by elevating hydrostatic pressure. Manothermosonication at 650 kPa and 140°C reduces protease activity to 6% and lipase activity to 7% of the residual activity reached after identical treatment times by simple heating at 140°C. At 110°C, manothermosonication reduces protease activity to 10−10 and lipase activity to 0.5% of the residual activity after simple heat treatment at the identical temperatures and times.