Enhanced remediation of petroleum in soil by petroleum-degrading bacterium strain TDYN1 and the effects of microplastics.

Abstract

Total petroleum hydrocarbons (TPH) are a kind of widely distributed pollutant, while its bioremediation in situ and how it is affected by microplastics (MPs) in soil remains unknown. A pot experiment was conducted to investigate the degradation capabilities of total petroleum hydrocarbons (TPH) by a novel petroleum hydrocarbon-degrading bacterium TDYN1 with different concentrations of microplastics PP and PE. The TDYN1 significantly enhanced TPH degradation rate at 42.4 ± 0.9%, compared to 12.1 ± 2.6% in the control. The microplastics affected the TPH degradation depended on their amount, and no difference in degradation rates between PP and PE. The 1% PP and PE facilitated the degradation of TPH, while the 4% PP and PE inhibited it after strain added. Strain TDYN1 increased the dehydrogenase, polyphenol oxidase and urease enzyme activities, and the number of TDYN1. After remediation, the pakchoi yield was increased by strain addition, but was reduced by PE, indicating a risk of TPH and PE combined pollution for vegetable growing. It helps to better understand the microbial remediation on TPH-microplastic compound-contaminated soil, and provide theoretical support for its evaluation of application.