Microbiome degrading linear alkylbenzene sulfonate in activated sludge

Area of Science:

• Environmental microbiology
• Biotechnology
• Wastewater treatment

Background:

• Linear alkylbenzene sulfonate (LAS) is a widely used anionic surfactant requiring biological alkane degradation in activated sludge (AS) processes.
• Increasing LAS consumption leads to higher loading in wastewater treatment plants (WWTPs), yet microbial involvement in LAS degradation remains understudied.

Purpose of the Study:

• To define microbiomes involved in LAS degradation in AS using metagenomic approaches.
• To investigate the abundance and diversity of alkane-degrading genes and their association with reconstructed metagenome-assembled genomes (MAGs).
• To explore the interactions between functional genes and MAGs in the context of LAS degradation.

Main Methods:

• Metagenomic sequencing to analyze microbial communities in AS.
• Investigation of alkane-degrading genes, including alkB and cytochrome P450.
• Reconstruction and analysis of metagenome-assembled genomes (MAGs).
• Assessment of gene-MAG associations and microbial interactions.

Main Results:

• Specific MAGs harbored alkB and cytochrome P450 genes, indicating specialized microbial players in LAS degradation.
• Diverse sets of genes with varying abundances were detected across samples.
• MAGs containing key degradation genes showed strong associations with other MAGs, suggesting positive commensal interactions.

Conclusions:

• Activated sludge microbiomes possess unique gene sets and MAGs for metabolizing LAS, particularly through ω-hydroxylation.
• Commensal interactions among microbial communities are vital for efficient LAS degradation in AS.
• Findings offer significant insights into the metabolic capabilities and ecological roles of AS microbiomes in surfactant removal.