Sodium chloride salting-in and microwave irradiation were combined to drive thermolysin molecules into mesoporous support to obtain efficiently immobilized enzyme. When the concentration of sodium chloride was 3 M and microwave power was 40W, 93.2% of the enzyme was coupled to the support by 3 min, and the maximum specific activity of the immobilized enzyme was 17,925.1 U mg(-1). This was a 4.5-fold increase in activity versus enzyme immobilized using conventional techniques, and a 1.6-fold increase versus free enzyme. Additionally, the thermal stability of the immobilized thermolysin was significantly improved. When incubated at 70 degrees C, there was no reduction in activity by 3.5 h, whereas free thermolysin lost most of its activity by 3 h. Immobilization also protected the thermolysin against organic solvent denaturation. The microwave-assisted immobilization technique, combined with sodium chloride salting-in, could be applied to other sparsely soluble enzymes immobilization because of its simplicity and high efficiency. (C) 2011 Elsevier Ltd. All rights reserved.