Overcoming microbial antagonism: strategic enhancements for dibenzofuran bioremediation

The ecological interaction networks governing microbiome dynamics during bioremediation of recalcitrant organic pollutants have garnered increasing attention; however, the molecular mechanisms underpinning negative interspecies interactions remain poorly characterized. This study investigates the antagonistic interplay between Rhodococcus sp. strain p52 (a dibenzofuran degrader) and Pseudomonas sp. YNh (an activated sludge isolate), and elucidates the mechanistic basis of their adverse interactions during dibenzofuran removal. In a synthetic consortium of strains p52 and YNh under iron-limited conditions, only 6.4 % of dibenzofuran was degraded. Strain YNh employed a dual interference strategy, secreting pyoverdine to competitively sequester iron and bacteriostatic pyocin, thereby impeding strain p52 growth and dibenzofuran catabolism. Transcriptional analysis revealed downregulation of genes involved in dibenzofuran degradation, siderophore synthesis, and iron transport in strain p52 within the consortium. Iron supplementation alleviated strain YNh-mediated inhibition. Notably, introducing Bacillus sp. Wb or salicylic acid enhanced dibenzofuran removal by 4.8- or 4.0-fold, respectively, through suppression of quorum sensing, pyocin production, and siderophore secretion in strain YNh. This work provides novel insights into bacterial antagonism and proposes targeted strategies to optimize bioremediation of recalcitrant organic contaminants.