Batch-to-batch variation and storage stability of the commercial peptidase preparation Flavourzyme in respect of key enzyme activities and its influence on process reproducibility

The synergy of endopeptidases and exopeptidases is the key for an efficient hydrolysis of proteins. Flavourzyme is sold as a commercial peptidase preparation from Aspergillus oryzae that exhibits various endo- and exopeptidase activities and, therefore, generates protein hydrolysates with high degrees of hydrolysis. The manufacturer (Novozymes) standardizes the enzyme preparation for one peptidase activity, determined with the marker substrate H-Leu- p NA. However, seven peptidases of Flavourzyme were recently identified and purified, and the significant contribution of six of them to wheat gluten hydrolysis was demonstrated. The knowledge about the batch-to-batch variation and storage stability of the Flavourzyme preparation regarding the other peptidase activities are still unclear, and this is important information for the usage of the enzyme preparation to gain reproducible protein hydrolysis processes. In the present study, we tested 12 Flavourzyme batches for the activity of the seven peptidases. The impact of the storage time on the peptidase activities and the magnitude of the batch-to-batch variation were investigated. In contrast to the activity determined with H-Leu- p NA as a substrate, the variations of the other peptidase activities were noticeable. The variation of the endopeptidase activity was most distinct and the activity decreased during the storage time of the preparation. The variation of the Flavourzyme composition also affected the reproducibility of a casein batch hydrolysis process, which should be taken into account for any future research and industrial application.