Pre-exposition to polycyclic aromatic hydrocarbons (PAHs) enhance biofilm formation and hydrocarbon removal by native multi-species consortium

ISAAC, PAULA; ALESSANDRELLO, MAURICIO JAVIER; MACEDO, ALEXANDRE JOSÉ; ESTÉVEZ, MARÍA CRISTINA; FERRERO, MARCELA ALEJANDRA

Journal of Environmental Chemical Engineering

Elsevier

Año: 2017 vol. 5 p. 1372 - 1378

2213-3437

In this work, a biofilm-mediated removal of polyaromatic hydrocarbons (PAHs) was proposed. PAHs are toxic and persistent contaminants from petroleum industry, dispersed on water, soils, air and sediments.The removal capabilities of C15 mixed culture of four indigenous strains of Pseudomonas and actinobacteria were successfully corroborated in a previous work. Results showed an interestingremoval behavior of planktonic C15 consortium, with degradation capabilities notably enhanced whencomparing with pure cultures. In the work reported in this paper, biofilm formation was evaluated inpure cultures and C15 defined consortium in order to propose a biofilm mediated immobilizationstrategy for bioremediation. Interestingly, a notable enhancement (approx. 180%) in biofilm formationwas observed after mixing the four species of C15 compared with pure cultures. Phenanthrene andpyrene also stimulated biofilm arrangement and biofilm-immobilized microorganisms demonstrated ahydrocarbon removal significantly higher than planktonic cells. Maximal removal values were 100% forphenanthrene and 78% for pyrene, after 7 days incubation. The biodegradation assay was divided intotwo stages: biofilm formation and hydrocarbon removal. The importance of PAHs presence duringbiofilm formation was evaluated. Although no differences in biofilm structure were observed,bioemulsifier production was enhanced and removal was accelerated when phenanthrene and pyrenewere added during biofilm formation stage. Even though more experiments must be conducted,considering the coexistence of Pseudomonas and actinobacteria groups during biodegradation and the improvement of removal performance, interspecies beneficial interactions could be suspected in thisnative multi-species biofilm.