SynCom improves carbon fixation capacity in phenanthrene-contaminated soils by reshaping microbial communities

Area of Science:

• Environmental microbiology
• Soil science
• Bioremediation

Background:

• Soil microorganisms are vital for carbon fixation, but organic pollutants like phenanthrene (PHE) impair these functions.
• Phenanthrene pollution significantly reduces soil carbon synthesis, posing environmental challenges.

Purpose of the Study:

• To construct and evaluate a synthetic community (SynCom) for mitigating phenanthrene's negative effects on soil.
• To assess the SynCom's impact on PHE degradation, carbon sequestration, and soil microbial community structure.

Main Methods:

• Construction of a SynCom with PHE-degrading bacterium (Sphingobium sp. RS2) and carbon-sequestering archaeon (Nitrososphaera viennensis EN76).
• Pot experiment to evaluate PHE removal, plant uptake reduction, and changes in soil carbon content.
• Application of random forest and partial least-squares path modeling (PLS-PM) to identify drivers of observed effects.
• Analysis of soil microbial diversity (α-diversity) and community interactions (network analysis).

Main Results:

• SynCom achieved 90.02% PHE removal from soil and reduced PHE transfer to lettuce by 81.07%.
• Significant increases in soil organic carbon, microbial carbon, and total carbon content were observed.
• SynCom enhanced bacterial and archaeal α-diversity, increased community modularity, robustness, and cooperation, and promoted keystone taxa associated with carbon synthesis.

Conclusions:

• The constructed SynCom effectively remediates phenanthrene pollution and enhances soil carbon sequestration.
• SynCom addition positively alters soil microbial community structure and function, increasing resistance to pollutants.
• This approach offers a promising strategy for addressing soil organic pollution and climate change simultaneously.