Challenging the impact of consortium diversity on bioaugmentation efficiency and native bacterial community structure in a freshly PAH-contaminated soil

Polycyclic aromatic hydrocarbons (PAHs) are priority pollutants. We studied the effect of bioaugmentation with three allochthonous bacterial consortia with increasing diversity, SC AMBk, SC1 and SC4, in the structure and functionality of an acutely PAH-contaminated soil microbiome. The PAH supplementation increased the resource availability and the inocula were able to: efficiently degrade the PAHs supplemented after 15 days of incubation, become temporary established, and modify the number of total interactions with soil residents. Sphingobium and Burkholderia, both member of inoculants, were the major contributors to KO linked to degradation and to differentially abundant genera in inoculated microcosms, indicating their competitiveness in the soil. Bioaugmentation efficiency relayed on them, while further degradation, could be carried out by native microorganism. This is the one of the first works which applied three inocula, designed from naturally occurring bacteria and study their effect on the soil native community through the ANCOM-BC. We revealed that when a resource that can be use by the inoculant is added to the soil, it is not necessary a high-diversity inoculant to interact with native community and establish itself. This result has implications in the design of microbiome engineering for bioremediation processes