Bioremediation of Historically Chlorimuron-Ethyl-Contaminated Soil by Co-Culture Chlorimuron-Ethyl-Degrading Bacteria Combined with the Spent Mushroom Substrate.

Hailian Zang,Chunyu Cui,Hailan Wang,Yue Wang,Ning Hou,Yi Cheng,Xuejiao An,Chunyan Li,Shanshan Sun,Wanjun Liu

doi:10.3390/microorganisms8030369

Hailian Zang, Chunyu Cui + Show 8 more

Open Access

https://doi.org/10.3390/microorganisms8030369

Copy DOI

Abstract

In this study, a novel chlorimuron-ethyl-degrading Pleurotus eryngiu-SMS-CB was successfully constructed for remediation of soil historically contaminated with chlorimuron-ethyl. The P. eryngiu-SMS-CB was prepared using efficient chlorimuron-ethyl-degrading cocultured bacteria, Rhodococcus sp. D310-1 and Enterobacter sp. D310-5, with spent mushroom substrate (SMS, a type of agricultural waste containing laccase) of Pleurotus eryngiu as a carrier. The chlorimuron-ethyl degradation efficiency in historically chlorimuron-ethyl-contaminated soil reached 93.1% at the end of 80 days of treatment with the P. eryngiu-SMS-CB. Although the P. eryngiu-SMS-CB altered the microbial community structure at the beginning of the 80 days, the bacterial population slowly recovered after 180 days; thus, the P. eryngiu-SMS-CB does not have an excessive effect on the long-term microbial community structure of the soil. Pot experiments indicated that contaminated soil remediation with P. eryngiu-SMS-CB reduced the toxic effects of chlorimuron-ethyl on wheat. This paper is the first to attempt to use chlorimuron-ethyl-degrading bacterial strains adhering to P. eryngiu-SMS to remediate historically chlorimuron-ethyl-contaminated soil, and the microbial community structure and P. eryngiu-SMS-CB activity in chlorimuron-ethyl-contaminated soil were traced in situ to evaluate the long-term effects of this remediation.

Highlights

Chlorimuron-ethyl (ethyl 2-(4-chloro-6-methoxypyrimidin-2-ylcarbamoylsulfamoyl) benzoate) is a long-term residual (2–3 years) sulfonylurea herbicide used to control important broadleaved weeds in soybean crops, and it is characterized by high efficiency, low toxicity and a broad spectrum [1]
The biodegradation of chlorimuron-ethyl has been revealed in previous studies, chlorimuron-ethyl-degrading strains that can be applied to remediate soil contaminated with chlorimuron-ethyl are lacking
Marínbenito et al reported that pesticides were absorbed by spent mushroom substrate (SMS), and Singh et al found that SMS contains laccase [14,15]

Summary

Introduction

Chlorimuron-ethyl (ethyl 2-(4-chloro-6-methoxypyrimidin-2-ylcarbamoylsulfamoyl) benzoate) is a long-term residual (2–3 years) sulfonylurea herbicide used to control important broadleaved weeds in soybean crops, and it is characterized by high efficiency, low toxicity and a broad spectrum [1]. It is necessary to find an effective method to decrease or remove the toxicity of chlorimuron-ethyl residue in contaminated soil. Bioremediation using chlorimuron-ethyl-degrading bacteria offers an efficient, economic, and safe method of eliminating chlorimuron-ethyl contamination, and biological methods are an eco-friendly approach compared to chemical and physical methods [4,5]. The biodegradation of chlorimuron-ethyl has been revealed in previous studies, chlorimuron-ethyl-degrading strains that can be applied to remediate soil contaminated with chlorimuron-ethyl are lacking. Yang et al used a solution containing the chlorimuron-ethyl-degrading strain CHL1 to remediate chlorimuron-ethyl-contaminated soil and investigated the lifetime of CHL1 and changes in the abundance of fungi and bacteria over the bioremediation period [6]. Degrading bacteria do not live long in liquid media because such media are contaminated; the preservation of these bacteria in liquid media is unsatisfactory [7]

Objectives

Methods

Results

Conclusion