Isolation of 2 simazine-degrading bacteria and development of a microbial agent for bioremediation of simazine pollution.

Jiangwei Zhu,Yan Zhao,Li Fu,Lei Wu,Jun Yin,Xiaolou Li,Rong Huang,Ning Yang

doi:10.1590/0001-3765202120210373

Abstract

Simazine was one of the most commonly used herbicides and was widely used to control broadleaf weeds in agriculture and forestry. Its widespread use had caused wide public concern for its high ecological toxicity. In order to remove simazine residues, 2 strains capable of effectively degrading simazine were isolated from the soil and named SIMA-N5 and SIMA-N9. SIMA-N5 was identified as Bacillus licheniformis by 16SrRNA sequence analysis, and SIMA-N9 was Bacillus altitudinis. According to the degradation ratio of simazine in a certain period of time, the degradation ability of different strains was evaluated. The degradation efficiency of simazine (5 mg/L) by SIMA-N9 could reach about 98% in 5d, and the strain SIMA-N5 could reach 94% under the same conditions. In addition, the addition of Pennisetum rhizosphere soil during the process of degrading simazine by strain SIMA-N9 could effectively improve the degradation efficiency. The strain SIMA-N9 has been developed as a microbial agent for the bioremediation of simazine contamination in soil. The new microbial agent developed by using SIMA-N9 has achieved satisfactory application effects. Based on the research results already obtained in this study, it was considered that strain SIMA-N9 and its live bacterial agent could play an important role in bioremediation of simazine pollution. This study could not only provide a set of solutions to the simazine pollution, but also provide a reference for the treatment of other pesticide pollution.

Highlights

The worldwide human population boost and expansion of industry and agriculture as well as climate change have resulted in a consequential increase in the chemical wastes upon natural ecosystems (Dauda et al 2019, Islam et al 2019)
2 simazine degrading strains were isolated from soil, and they were Bacillus licheniformis SIMA-N5 and Bacillus altitudinis SIMA-N9, respectively
The combined application of strain SIMA-N5 and strain SIMA-N9 could not achieve higher degradation efficiency, which should be attributed to the competition or antagonism between the two strains

Summary

Introduction

The worldwide human population boost and expansion of industry and agriculture as well as climate change have resulted in a consequential increase in the chemical wastes upon natural ecosystems (Dauda et al 2019, Islam et al 2019). In agricultural production, the extensive use of pesticides such as herbicides, insecticides and fungicides has caused serious adverse effects on the environment. Simazine (CAS:122-34-9) was one of the most commonly used s-triazine herbicides and was widely used to control broadleaf weeds in agriculture and forestry, especially in sugarcane, corn and orchard fields (Li et al 2018, Silva & Iyer 2014). Its widespread use has caused wide public concern for its moderate persistent in the soil and aquatic environments and high ecological toxicity (Morgante et al 2010, 2012, Garmouma et al 2001). In many European countries, simazine was prohibited due to its potential endocrine and

Methods

Results

Conclusion