Bioaugmentation effect and mechanism of polycyclic aromatic hydrocarbons (PAHs) degradation using Arthrobacter sp. SZ-3 and Pseudomonas putida B6-2 under high Tween80 stress

This study examines investigates the use of Tween80 as a typical solubilizer in the remediation of PAH-contaminated soil and explores the advantages of combined elution-microbial degradation in overcoming the inhibitory effect of high-concentration eluents. A microbial synergistic strategy system was proposed using Arthrobacter sp. SZ-3 and Pseudomonas putida B6-2 as the key bacteria in the presence of Tween80. The results indicate that in systems where Tween80 is present, the SZ-3 strain has a strong ability to degrade three kinds of PAH compounds. The B6-2 strain demonstrates multiple pathways for PAH degradation. Mixed bacteria exhibit degradation rates 60.7% higher than single bacteria at different concentrations of Tween80. Additionally, the average growth rates of mixed bacteria increased by 1.17–1.37 times, which is consistent with the changes in functional group. The detection results of protein activity within each degradation system corresponded with the growth quantity and the cyclic variation characteristics of ETS enzyme activity. Notably, the ETS of mixed bacteria was 150% higher than that of single bacteria. At a Tween80 concentration of 500 mg/L, the degradation rates of PAHs (Phe, Flu, Pyr) by mixed bacteria were 5.7%-20.7%, 8.5%-22.0%, 6.6%-22.2% higher than those of single bacteria. It was observed that the catechol 1,2-dioxygenase activity of mixed bacteria with was 2.3 times higher than of the single bacteria under the condition of 500 mg/L Tween80. The presence of Tween80 did not affect the PAH degradation pathways, but it did significantly impact the amount and duration of accumulation of the characteristic intermediate product.