Expanding the Functionality of an Autoinduction Device for Repression of Gene Expression in Bacillus subtilis .

Autonomous control of gene expression through engineered quorum-sensing processes is broadly applicable to biosynthetic pathways, including simultaneous control of different genes. It is also a powerful tool for balancing growth and production. We had previously engineered a modular autoinduction device for the control of gene expression in B. subtilis . Now, we expand its functionality to repress gene expression autonomously. The engineered R8 promoter responds to AHL accumulation in the culture medium. In a riboflavin-producing strain, the AHL-Lux complex exerts 5-fold repression on the R8-driven expression of the flavokinase/FAD synthetase gene ribC , resulting in a higher titer of the vitamin. We engineered a strain able to autonomously induce and repress different genes simultaneously, demonstrating the potential of the device for use in metabolic engineering.