Transcriptomic impact of PrsA over-expression during fed-batch Bacillus subtilis alpha-amylase fermentation. Transcriptomic impact of PrsA over-expression during fed-batch Bacillus subtilis alpha-amylase fermentation

The production of alpha-amylase (AMY) enzyme in Bacillus subtilis at a high rate leads to accumulation of unfolded AMY, which causes secretion stress. The over-expression of the PrsA chaperon aids the enzyme folding and thus reduces stress. Stress pathways are complex and intertwined in regulation of a variety of cellular mechanism; for instance, PrsA over-expression leads to reduced cell growth. To capture an overview over the impacted mechanisms, we analyze the transcriptomic changes during fed-batch AMY fermentation between a PrsA over-expressing strain and a control in a time-series RNA-seq experiment (n=3, 6 timepoints). We found evidence of transcription in 542 previously un-annotated regions, of which 234 had significant changes in transcription levels (Overall FDR 0.01). The pairwise comparison of up-/downregulated genes and their over-representation in biological processes (FDR 0.01) suggest that the PrsA over-expression might alter ATP biosynthesis activity, amino acid metabolism, and cell wall stability. An additional investigation of the protein-protein association network highlights potential cell motility signaling. Overall, these highlighted mechanisms could potentially further reduce secretion stress or detrimental aspects of PrsA over-expression during AMY production. Overall design: RNA-seq study of fed-batch AMY fermentation over time compared between a PrsA over-expressing strain and a control