S60: Engineering interspecies communication in synthetic microbial consortia

The biosynthesis of compounds of medical and industrial importance often requires engineering and optimization of complex metabolic pathways. There are many limitations of using a single population of microorganism that could be alleviated or addressed by using a mixed community, including metabolic load and the number of exogenous elements that can be cloned and optimized in a single cell. In order to control interactions and complex dynamics required for these cells to work together, it is important to generate robust communication pathways between biotechnologically relevant species. In this presentation, we describe a new set of transcriptional regulators, promoters and a synthetic communication pathway between a representative Gram-negative organism (Escherichia coli) and representative Gram-postitive organism (Bacillus megaterium). An acyl-homoserine lactone (AHL)-dependent system was adapted to send signals from B. megaterium to E. coli. Both heterologous expression of the gene required for AHL synthesis and manipulation of the acyl-acyl carrier protein pool to include more straight chain lipids was required to enable AHL production in B. megaterium. Components of a peptide-dependent microbial signaling pathway were used to send signals from E. coli to B. megaterium. Both communication systems have been shown to function in co-cultures. We anticipate that our communication system, when combined with strategies for fine-tuning ecological interactions, will be a key technology for the implementation of synthetic consortia for bioprocessing and metabolic engineering applications.