Open Access

Katharina J. Ost, Mareike E. Dirks-Hofmeister

• The production of food-grade substances and complex biocatalysts used as additives or active ingredients – mainly for food applications – can be achieved in the eukaryotic expression system of Aspergillus niger. Food proteins or food enzymes e.g., casein, ovalbumin, phytase or glucoamylase are highly complex polymers. Most of them could be used as nitrogen or energy source for animals and humans, while others are industrial relevant biomass-degrading enzymes used for biological waste processing and food production. However, the successful production of novel recombinant proteins can be challenging, resource- and time consuming. Therefore, A. niger mutant libraries are needed to understand the “adjusting screws” to produce high yields of recombinant proteins, preferably even in a kind of generic, transferable system. In order to establish a universal and multipurpose expression platform, there is the need to overcome the lack of high throughput assays first. To tackle this problem, we designed a modular, quantitative and feasible high-throughput screening system to express and screen recombinant proteins regarding their stability and functionality in A. niger. For this purpose a dual-luciferase reporter gene system, which is applicable in small scale will be established for A. niger. After the generation of an A. niger secretion mutant library, the system will be transferred and tested to other proteins of interest. The technology can be integrated into bio-regenerative life support systems for the autonomous production of e.g., food, food additives and food enzymes on earth as well as in deep-space.