Mechanism of Phanerochaete chrysosporium-mediated tetracycline hydrochloride removal promoted by low-dose silver nanoparticles

The influence of silver nanoparticles (AgNPs) on environmental microorganisms has been extensively reported, however, there is currently limited understanding of effects of stress-induced by AgNPs on other pollutant degradation. In this study, Phanerochaete chrysosporium was stimulated by different concentrations of AgNPs to explore its effect on P. chrysosporium-mediated degradation of tetracycline hydrochloride (TCH). The results indicate that treatment with AgNPs at low concentration resulted in a considerable increase in TCH degradation, TCH degradation reached a maximum of 97% with 0.1 mg L-1 AgNPs treated after 3 d, and the viability of P. chrysosporium increased 1.48 times compared with the control group. The largest O-2 influx of -17 pmol cm(-2) s(-1) under 0.1 mg L-1 AgNPs treatment reveal the enhancement of P. chrysosporium respiration. In addition, low concentrations of AgNPs could induce the overexpression of cytochrome P450 and extracellular degradation enzymes MnP-related genes in stimulated cells, which further induce the production of extracellular degrading enzymes (51.0 U L-1 MnP and 23.7 U L-1 LiP) to accelerate the degradation of TCH. Together, our combined results uncovered the enhanced degradation mechanisms of P. chrysosporium induced by which AgNPs under sublethal dosage.

Automated summary

This study found that low concentration treatment of AgNPs can enhance the degradation ability of P. chrysosporium towards TCH, increasing its viability and oxygen influx rate. Additionally, low concentrations of AgNPs can induce the overexpression of cytochrome P450 and extracellular degradation enzymes MnP-related genes in stimulated cells, leading to increased production of extracellular degrading enzymes and accelerated degradation of TCH.