Biology subjects

Festa, S.

Publications and source records attributed to Festa, S..

3 recordsLinked to original sources

bioRxiv2025

Improving PAH-chronically contaminated soil bioremediation using a combined strategy of bioaugmentation and surfactant-enhanced biostimulation

Aged polycyclic aromatic hydrocarbon (PAH)-contaminated soil represents a challenge for the application of an effective bioremediation strategy, as the low PAH bioavailability limits microbial degradation. This study aimed to compare the effect of bioaugmentation (BA) and the coupled strategy of bioaugmentation and biostimulation (BA-SEB) on a chronically hydrocarbon-contaminated soil (IPK). For BA, we compared the performance of three PAH-degrading consortia with increasing diversity: SC AMBk, SC1, SC4. For BA-SEB, we coupled inoculation with these consortia with the addition of Triton X-100 surfactant, at sub-critical micelle concentration dose. In the BA microcosms, inoculation did not result in significant degradation of the determined PAH after 58 days of incubation. Among the BA-SEB microcosms, SC4 inoculated ones and the non-inoculated control showed significant degradation of fluoranthene, chrysene, and pyrene during the incubation period. Notably, BA-SEB microcosms inoculated with SC4 achieved superior pyrene degradation compared to the others. Both inoculation and the addition of surfactant impacted the community assembly, with the surfactant exerting the major effects. The surfactant addition stimulated several genera related to the degradation of PAH (Novosphingobium, Blastomonas). In addition, co-occurrence network analysis revealed that in SC4 inoculated microcosms most of these genera were positively correlated with the inoculated genera, particularly with Paraburkholdeira genus. The application of the combined strategy using the SC4 consortium in IPK soil successfully stimulated PAH biodegradation, demonstrating the importance of inoculant diversity and the identity of the consortium members under increased stress conditions (i.e from acute to aged contamination) for the strategys success.

microbiology↗

bioRxiv2024

Challenging the impact of consortium diversity on bioaugmentation efficiency and native 1 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

microbiology↗

bioRxiv2024

Analysis of predation-driven inoculum loss and carbon flow in bioaugmented soils through DNA-SIP

Bioaugmentation is considered as a sustainable and cost-effective methodology to recover contaminated environments, but its outcome is highly variable. Predation is a key top-down control mechanism affecting inoculum establishment, however its effects on this process have received little attention. This study focused on the impact of trophic interactions on bioaugmentation success in two soils with different pollution exposure histories We inoculated a 13C-labelled pollutant-degrading consortium in these soils and tracked the fate of the labelled biomass through stable isotope probing (SIP) of DNA. We identified active bacterial and eukaryotic inoculum-biomass consumers through amplicon sequencing of 16S rRNA and 18S rRNA genes coupled to modified enrichment factor calculation. Inoculation effectively increased PAH removal in short-term polluted soils but not in long-term polluted soils. A decrease in the relative abundance of the inoculated genera was observed already on day 15 in the long-term polluted soil, while growth of these genera was observed in the short-term polluted soil, indicating establishment of the inoculum. In both soils, eukaryotic genera dominated as early incorporators of 13C-labelled biomass, while bacteria incorporated the labelled biomass at the end of the incubation period, probably through cross-feeding. We also found different successional patterns between the two soils. In the short-term polluted soil, Cercozoa and Fungi genera predominated as early incorporators, whereas Ciliophora, Ochrophyta and Amoebozoa were the predominant genera in the long-term polluted soil. Our results showed differences in the inoculum establishment and predator community behaviours, affecting bioaugmentation efficiency. This highlights the need to further study predation effects on inoculum survival to increase the applicability of inoculation-based technologies.

microbiology↗