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 °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 °C). The MTG activity retention in dried preparations during storage at 4 °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.