Lignin-enhanced fungal-bacterial consortium for degradation of petroleum hydrocarbon contaminants

A lignin-enhanced fungal-bacterial consortium strategy (Bau_Lignin) was proposed to promote the biodegradation of petroleum hydrocarbon contaminants (PHCs), with pyrene and n-docosane selected as representative compounds. Optimal performance was achieved by co-inoculating fungi and bacteria at a 5:5 ratio. Within 12 days, the pyrene removal efficiency of Bau_Lignin was 2.23 times and 1.67 times higher than that of the bacterial consortium (XH40) and the fungal-bacterial consortium (Bau), respectively. Lignin addition enhanced enzyme activities (e.g., ligninolytic enzymes, dioxygenases, dehydrogenases) and increased the abundance of key functional genera (e.g., Pseudomonas, Achromobacter, Stenotrophomonas). Metagenomic sequencing further revealed an enrichment of genes associated with biosurfactant production and oxygenase activity in Bau_Lignin, facilitating mass transfer, hydroxylation, and ring-cleavage processes. Thus, a potential reinforcement mechanism was proposed, highlighting the synergistic interactions among enzyme activities, functional genera, and key functional genes across multiple pathways.