TY - JOUR
T1 - Specific enrichment of hydrocarbonclastic bacteria from diesel-amended soil on biochar particles
AU - Assil, Zhansaya
AU - Esegbue, Onoriode
AU - Mašek, Ondřej
AU - Gutierrez, Tony
AU - Free, Andrew
N1 - Funding Information:
We thank Franziska Srocke, Tom Wagner, Julia de Rezende and Hanna Peach for helpful discussions and assistance with access to facilities, Dan Nussey and Hannah Lemon for access to and assistance with the QIAcube Connect, and Maggie Knight and Heather Barker for assistance with the microcosm experiment. We are grateful to the MSc Biotechnology programme at the University of Edinburgh for financial support. ZA was supported by a Bolashak International Scholarship. Illumina DNA sequencing was carried out by Edinburgh Genomics at the University of Edinburgh, which is partly supported through core grants from NERC ( R8/H10/56 ), MRC ( MR/K001744/1 ) and BBSRC ( BB/J004243/1 ).
Publisher Copyright:
© 2020 Elsevier B.V.
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2021/3/25
Y1 - 2021/3/25
N2 - Biochar has been proposed as a suitable biostimulant for the remediation of hydrocarbon contamination, and also has the potential to act as a carrier for hydrocarbonoclastic microorganisms which could bioaugment endogenous microbial communities. However, the evidence regarding the biostimulatory effects of biochars on hydrocarbon bioremediation is somewhat equivocal, possibly due to variability of the physicochemical properties of biochar and soil across studies. Here, we use standard biochars with defined properties produced from softwood pellets (SWP) and rice husk (RH) at pyrolysis temperatures of 550 °C or 700 °C to test the effects of biochar amendment on microbial community composition and hydrocarbon degradation in soil microcosms contaminated with diesel oil. Combining this approach for the first time with specific analysis of microbial community composition using amplicon sequence variants (ASVs), we find that oil contamination causes extreme short-term loss of soil microbial diversity, and highly-specific selection of a limited set of genera defined by 13 ASVs. Biochar ameliorates the short-term loss of diversity, and in the longer term (9 weeks), changes community composition in a type-specific manner. The majority of the 13 selected ASVs are further enriched on biochar particles, although SWP biochars perform better than RH biochar in enrichment of putative hydrocarbonoclastic Aquabacterium spp. However, complete degradation of normal (n) alkanes from the aliphatic hydrocarbon fraction is prevented in the presence of biochar amendment, possibly due to their adsorption onto the char surface. Furthermore, we show that putative hydrocarbon degraders released from diesel-amended soil can subsequently be enriched to high levels on SWP biochar particles in growth medium supplemented with diesel oil as the sole carbon source; these include selected ASVs representing the genera Rhodococcus, Aquabacterium, and Cavicella. This work suggests that use of biochar pre-enriched with endogenous, conditionally-rare hydrocarbon degrading bacteria is a promising strategy for bioaugmentation of diesel-contaminated soils.
AB - Biochar has been proposed as a suitable biostimulant for the remediation of hydrocarbon contamination, and also has the potential to act as a carrier for hydrocarbonoclastic microorganisms which could bioaugment endogenous microbial communities. However, the evidence regarding the biostimulatory effects of biochars on hydrocarbon bioremediation is somewhat equivocal, possibly due to variability of the physicochemical properties of biochar and soil across studies. Here, we use standard biochars with defined properties produced from softwood pellets (SWP) and rice husk (RH) at pyrolysis temperatures of 550 °C or 700 °C to test the effects of biochar amendment on microbial community composition and hydrocarbon degradation in soil microcosms contaminated with diesel oil. Combining this approach for the first time with specific analysis of microbial community composition using amplicon sequence variants (ASVs), we find that oil contamination causes extreme short-term loss of soil microbial diversity, and highly-specific selection of a limited set of genera defined by 13 ASVs. Biochar ameliorates the short-term loss of diversity, and in the longer term (9 weeks), changes community composition in a type-specific manner. The majority of the 13 selected ASVs are further enriched on biochar particles, although SWP biochars perform better than RH biochar in enrichment of putative hydrocarbonoclastic Aquabacterium spp. However, complete degradation of normal (n) alkanes from the aliphatic hydrocarbon fraction is prevented in the presence of biochar amendment, possibly due to their adsorption onto the char surface. Furthermore, we show that putative hydrocarbon degraders released from diesel-amended soil can subsequently be enriched to high levels on SWP biochar particles in growth medium supplemented with diesel oil as the sole carbon source; these include selected ASVs representing the genera Rhodococcus, Aquabacterium, and Cavicella. This work suggests that use of biochar pre-enriched with endogenous, conditionally-rare hydrocarbon degrading bacteria is a promising strategy for bioaugmentation of diesel-contaminated soils.
KW - Amplicon sequence variant
KW - Bioaugmentation
KW - Biochar
KW - Conditionally-rare taxa
KW - Hydrocarbon contamination
KW - Soil biostimulation
UR - http://www.scopus.com/inward/record.url?scp=85094828173&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2020.143084
DO - 10.1016/j.scitotenv.2020.143084
M3 - Article
C2 - 33131874
SN - 0048-9697
VL - 762
JO - Science of the Total Environment
JF - Science of the Total Environment
M1 - 143084
ER -