Bacillus subtilis as a cell factory for bio-based production processes

The objective of this thesis was to better explore the metabolic potential of Bacillus subtilis, by analyzing and comparing production of primary and secondary metabolites in various food-grade, spore-deficient strains and industrially used strains. In chapter 2 it was demonstrated that by selecting different strains of B. subtilis, the application range of this bacterial species can be significantly expanded. Subsequently, the food ingredient pulcherrimin (chapter 3) that can be used as antimicrobial agent and the (biobased) chemical pyridine-2,6-dicarboxylic acid (chapter 4), which can serve as the precursor for biopolymers, were selected as case studies to explore the feasibility of developing B. subtilis as a cell factory for biotechnologically valuable compounds. Additionally,   a method that can facilitate high-throughput detection of pyridine-2,6-dicarboxylic acid in fermentation broths was developed (chapter 5). The latter provides an efficient tool enabling unbiased screening of the compound’s production. The work led to novel insights for the construction of B. subtilis based cell factories designed for pyridine-2,6-dicarboxylic acid production. In summary, this study demonstrates the potential use of B. subtilis beyond enzyme production and further highlights its contribution to the bio-based economy.