Stabilization of a new microbial transglutaminase from Streptomyces hygroscopicus WSH03-13 by spray drying

Effect of some additives on the thermal stability of a new microbial transglugaminase from Streptomyces hygroscopicus WSH03-13, and the stabilization of MTG by spray drying were studied and compared with freeze-drying method. It was observed that MTG was not stable at 50 degrees C (loss of over 50% after 30 min of incubation) and became more sensitive to heat in the presence of ethanol. The addition of carbohydrates such as: maltodextrin, sucrose, mannose, trehalose, and reduced glutathione (GSH), evidently enhanced enzyme thermal stability. The highest activity yield of spray drying reached about 90% with the combined addition of maltodextrin and GSH at the recommended concentrations and at a lower air outlet temperature (60 +/- 3 degrees C). The MTG activity retention in dried preparations during storage at 4 degrees C for 60 days was mainly related to the moisture content. Lower moisture content and the addition of proper stabilizers could improve the storage stabilization and thermal stability of enzyme preparations. (c) 2006 Elsevier Ltd. All rights reserved.