Bioremediation of alkane–containing saline soils using the long–chain alkane–degrading bacterium Pseudomonas aeruginosa DL: Effects, communities, and networks

Abstract

Remediation of soil contaminated with long–chain hydrocarbons and affected by salinization poses a considerable challenge. The isolation of a bacterial strain, identified as Pseudomonas aeruginosa DL, from petroleum–contaminated saline–alkali soil has been reported in this study. The strain demonstrated a high capacity to degrade long–chain alkanes and exhibited adaptability to saline–alkali conditions. Gene annotation and analysis of degradation products revealed that the strain DL employed a step–by–step chain–breaking mechanism to degrade long–chain alkanes. Following 160 days of bioaugmented remediation of contaminated soil using the strain DL, 81.36% degradation of long–chain alkanes, initially present at a concentration of 30,000 mg/kg, was achieved. The activities of soil enzymes, including dehydrogenase, lipase, catalase, and urease, were significantly increased (p < 0.05). Community structure analysis revealed that Pseudomonas aeruginosa DL successfully colonized the contaminated soil, achieving a relative abundance of 69%. In addition, alkane–degrading bacterial genera, such as Salinimicrobium, Isoptericola, Gordonia, Achromobacter and Ochrobactrum, emerged as new dominant genera. Microbial cooccurrence networks confirmed that bioaugmentation with the strain DL could streamline interpopulation interactions within the community and enhance associative networks, thereby guiding community evolution toward improved alkane degradation. This study offers valuable strain resources and data support for the bioremediation of saline–alkali soils contaminated with long–chain alkanes.