A modular autoinduction device for control of gene expression in Bacillus subtilis.

Intense synthesis of proteins and chemicals in engineered microbes impose metabolic burden, frequently leading to reduced growth and heterogeneous cell population. Thus, the correct balance between growth and production is important. Such balance can be engineered through dynamic control of pathways, but few broadly applicable tools are available to achieve this. We present an autonomous control of gene expression mediated by quorum sensing in Bacillus subtilis, able to self-monitor and induce expression without human supervision. Two variations of the induction module and seven of the response module were engineered generating a range of induction folds and strengths for gene expression control. Our strongest response promoter is 2.5 and 3.2 times stronger than the well-characterized promoters PsrfA and Pveg, respectively. We applied our strongest autoinduction device for the production of the vitamin B2. This study presents a toolbox of autoinduction modules for B. subtilis that is modular and tunable.