Specific enrichment of hydrocarbonclastic bacteria from diesel-amended soil on biochar particles

Biochar has been proposed as a suitable biostimulant for the remediation of hydrocarbon contamination, and also potential to act carrier hydrocarbonoclastic microorganisms which could bioaugment endogenous microbial communities. However, evidence regarding biostimulatory effects biochars on bioremediation is somewhat equivocal, possibly due variability physicochemical properties biochar soil across studies. Here, we use standard with defined produced from softwood pellets (SWP) rice husk (RH) at pyrolysis temperatures 550 °C or 700 test amendment community composition degradation in microcosms contaminated diesel oil. Combining this approach first time specific analysis using amplicon sequence variants (ASVs), find that oil contamination causes extreme short-term loss diversity, highly-specific selection limited set genera by 13 ASVs. ameliorates longer term (9 weeks), changes type-specific manner. The majority selected ASVs are further enriched particles, although SWP perform better than RH enrichment putative Aquabacterium spp. complete normal (n) alkanes aliphatic fraction prevented presence amendment, their adsorption onto char surface. Furthermore, show degraders released diesel-amended can subsequently be high levels particles growth medium supplemented sole carbon source; these include representing Rhodococcus, Aquabacterium, Cavicella. This work suggests pre-enriched endogenous, conditionally-rare degrading bacteria promising strategy bioaugmentation diesel-contaminated soils.