On the safety of a new generation of DSM Aspergillus niger enzyme production strains

Abstract

Consumers safety of enzyme preparations is determined by three variables: the producing organism, the raw materials used in the production, and the production process itself. The latter one is embedded in current Good Manufacturing Practice (cGMP) and Hazard Analysis of Critical Control Points (HACCP); therefore the safety focus can be directed to raw materials and the producing organism. In this paper, we describe the use of novel genetically modified strains of Aspergillus niger-made by a design and build strategy-from a lineage of classically improved strains with a history of safe use in enzyme production. The specifics of the host strain allow for integration and over-expression of any gene of interest at a targeted integration site implying that the rest of the host genome is not affected by this integration. Furthermore due to the fact that the newly integrated gene copies are put under the genetic regulation of the host's own glucoamylase promoter, the recipe of the production process of any new production strain can be kept constant with respect to the raw materials composition. Consequently the safety of a new enzyme product from these novel genetically modified strains is determined by the background of the production organism. The use of a strain with a history of safe use and targeted integration according to the concept described above has consequences for the safety studies on the final product. If a known enzymatic activity is over-expressed the safety of a new enzyme preparation is covered by the results of the safety studies performed for other strains from this specific Aspergillus niger strain lineage. In this paper an overview is given on the available toxicity tests with these strains. We conclude that for new enzyme products produced with strains from this lineage using the design and build technology no new sub-acute/chronic oral toxicity studies are needed. This also has the benefit that no longer test animals are needed to demonstrate the safety of products produced by these strains.