Characterization of fluoranthene degradation by the novel isolated Pseudomonas xizangensis S4 and its application potential immobilized in potassium humate-modified biochar.

Enhanced microbial remediation represents a promising technique for the removal of polycyclic aromatic hydrocarbons (PAHs). However, high-efficiency remediation agents remain limited, including microbial resources and remediation materials. In this study, a novel strain of Pseudomonas xizangensis S4 was isolated from plateau lake sediment, exhibiting a fluoranthene degradation rate of 41.90 % at 50 ppm within 7 d. The key degradation genes identified through genomic and transcriptomic analyses included ndmC, dmpK, dmpB, and dmpH. The metabolites detected via GC-MS analysis were biphenyls, parabens, and phthalate esters. Based on the above results, the degradation mechanisms of fluoranthene were deduced. Furthermore, an efficient remediation agent was developed, utilizing potassium humate-modified biochar to immobilize bacterial cells. The developed remediation agent enhanced the removal efficiency by 16.71 % compared to the single strain. Thus, the application of potassium humate-modified biochar for the immobilization of P. xizangensis S4 represents a promising method for the remediation of PAH-contaminated soil.