AHL signaling molecules with a large acyl chain enhance biofilm formation on sulfur and metal sulfides by the bioleaching bacterium Acidithiobacillus ferrooxidans.

Alex González , Sören Bellenberg , Sigde Mamani , Lina Ruiz , Alex Echeverría , Laurent Soulère (1) , Alain Doutheau (1) , Cecilia Demergasso , Wolfgang Sand , Yves Queneau (1) , Mario Vera , Nicolas Guiliani

1 COB - Chimie Organique et Bioorganique

Biofilm formation plays a pivotal role in bioleaching activities of bacteria in both industrial and natural environments. Here, by visualizing attached bacterial cells on energetic substrates with different microscopy techniques, we obtained the first direct evidence that it is possible to positively modulate biofilm formation of the extremophilic bacterium Acidithiobacillus ferrooxidans on sulfur and pyrite surfaces by using Quorum Sensing molecules of the N-acylhomoserine lactone type (AHLs). Our results revealed that AHL-signaling molecules with a long acyl chain (12 or 14 carbons) increased the adhesion of A. ferrooxidans cells to these substrates. In addition, Card-Fish experiments demonstrated that C14-AHL improved the adhesion of indigenous A. ferrooxidans cells from a mixed bioleaching community to pyrite. Finally, we demonstrated that this improvement of cell adhesion is correlated with an increased production of extracellular polymeric substances. Our results open up a promising means to develop new strategies for the improvement of bioleaching efficiency and metal recovery, which could also be used to control environmental damage caused by acid mine/rock drainage.

Domaines: Chimie organique

Alex González, Sören Bellenberg, Sigde Mamani, Lina Ruiz, Alex Echeverría, et al.. AHL signaling molecules with a large acyl chain enhance biofilm formation on sulfur and metal sulfides by the bioleaching bacterium Acidithiobacillus ferrooxidans.. Applied Microbiology and Biotechnology, 2013, 97 (8), pp.3729-37. ⟨10.1007/s00253-012-4229-3⟩. ⟨hal-00919253⟩