Engineering PQS Biosynthesis Pathway for Enhancement of Bioelectricity Production in Pseudomonas aeruginosa Microbial Fuel Cells

Abstract

The biosynthesis of the redox shuttle, phenazines, in Pseudomonas aeruginosa, an ubiquitous microorganism in wastewater microflora, is regulated by the 2-heptyl-3,4-dihydroxyquinoline (PQS) quorum-sensing system. However, PQS inhibits anaerobic growth of P. aeruginosa. We constructed a P. aeruginosa strain that produces higher concentrations of phenazines under anaerobic conditions by over-expressing the PqsE effector in a PQS negative ΔpqsC mutant. The engineered strain exhibited an improved electrical performance in microbial fuel cells (MFCs) and potentiostat-controlled electrochemical cells with an approximate five-fold increase of maximum current density relative to the parent strain. Electrochemical analysis showed that the current increase correlates with an over-synthesis of phenazines. These results therefore demonstrate that targeting microbial cell-to-cell communication by genetic engineering is a suitable technique to improve power output of bioelectrochemical systems.

Functional Amyloids Keep Quorum-sensing Molecules in Check

“…Thus, pqsABCDE expression indicates interaction of PQS with the cell (31). The P. aeruginosa PAO1 ⌬pqsC mutant, which is unable to synthesize the PQS precursor HHQ, was obtained from a transposon mutagenesis library screen (31). The 3-oxo-C12-HSL reporter strain was obtained by introducing a P lasB ::gfp(ASV) transcriptional fusion and an extra copy of lasR under the influence of the lac promoter, which is constitutively expressed in P. aeruginosa into P. aeruginosa PAO1 ⌬lasI⌬rhlI via a mini-Tn5 insert, as described by Yang et al (32).…”

Isolation of phenazine 1,6-di-carboxylic acid from Pseudomonas aeruginosa strain HRW.1-S3 and its role in biofilm-mediated crude oil degradation and cytotoxicity against bacterial and cancer cells

“…The phenazine compounds play a significant role in bacterial interaction and have potential biotechnological applications. Microbial cell to cell communication had recently been employed in bioelectricity generation where overproduction of phenazine was observed with increase in current density (Wang et al 2013). The compounds have diverse physicochemical properties and activities such as pigmentation, oxidation-reduction, electron acceptor, biosensor, and anti-tumor activities (Parsons et al 2004;Price-Whelan et al 2006).…”

Comparative genome analysis reveals genetic adaptation to versatile environmental conditions and importance of biofilm lifestyle in Comamonas testosteroni

“…Culture was growing in minimal M9 medium supplemented with 30 μM FeCl 3 for ironrich conditions or deferrated with 30 μM 2,2′-bipyridine for iron-deficient conditions. Siderophore-producing Pseudomonas aerugnosa PAO1 (ATCC 15692) was used as a positive control (Mohanty et al 2015;Wang et al 2013). Filtered supernatant was mixed with equal volume of CAS assay solution.…”