(135b) Engineering of Quorum Sensing Molecules for Biodegradation, Bioelectricity Generation, and Nano-Material Biosynthesis By Whole-Cell Biocatalysts

Quorum sensing (QS) is widely conserved in bacterial cell-cell communication systems and plays an important role in many biological processes. This work demonstrates that engineering of QS molecules contributes to bioelectricity generation and nanomaterial synthesis by Pseudomonas aeruginosa, in addition to its impact on toxic aromatics biodegradation. In microbial fuel cells (MFCs) system under different QS expression patterns, we found that P. aeruginosa could use different electron shuttles. By overexpressing rhl QS system, more electricity generation with broader potential range from -0.40 V to 0 V was reached compared to non-engineered whole-cell biocatalysts. The electrochemical and high performance liquid chromatography analyses indicated that the electron shuttle produced by the rhl overexpression cells was phenazines - pyocyanin and phenazine-1-carboxylate, a type of efficient electron shuttle. The rhl QS system was also found significant to carbon nanomaterial biosynthesis by P. aeruginosa. By overexpressing rhl QS, carbon nanomaterial was synthesized faster by the engineered biocatalysts. More interestingly, the rhlIR double mutant could not synthesize the nanomaterial even with addition of N-butyryl-L-homoserine lactone (BHL, a signaling molecule of rhl QS system); but the rhlI single mutant could synthesize under BHL addition, which will be discussed in this presentation. The information obtained shows good potential of P. aeruginosa as whole-cell biocatalysts for bioelectricity production and nanomaterial biosynthesis by QS engineering.