Burkholderia thailandensis: the Main Bacteria Biodegrading Fipronil in Fertilized Soil with Assessment by a QuEChERS/GC-MS Method

Abstract

Due to the expansion of sugarcane crops and the high costs of agricultural inputs, an alternative for fertilization of the soil is the use of humic substances (HS) because they improve its physical-chemical properties. The objective of this study was to assess the biological degradation of fipronil in soil supplemented with HS. For determination of fipronil and its metabolites, we validated a quick, easy, cheap, effective, rugged, and safe gas chromatography-mass spectrometry (QuEChERS/GC-MS) method, which yielded detection and quantification limits of 15.0 and 62.5 ng g −1 , respectively. The method presented linearity of 0.99, precision between 1.5 and 10.9%, while the recovery ranged from 78 to 98%, with precision (relative standard deviation (RSD)) < 5%. The strain B. thailandensis of Burkholderia sp. grew under typical conditions for degradation of fipronil. Eight treatments assessed the degradation by B. thailandensis in the presence of HS. The metabolites produced in the experiment, although detected, could not be quantified because they were below the limit of quantification of the method. Our results showed that B. thailandensis has the potential to degrade fipronil, and that HS is not toxic to the microbiota, and does not inactivate fipronil.

Fipronil biodegradation and metabolization by Bacillus megaterium strain E1

“…To date, only a few studies on fipronil biodegradation have been conducted. 1,18,24,[33][34][35][36]38,41 Furthermore, only Paracoccus sp., 1 B. thuringiensis, 29 B. firmus, 39 Stenotrophomonas acidaminiphila, 41 Burkholderia thailandensis, 32 Staphylococcus arlettae, Bacillus thuringiensis, 37 Streptomyces rochei strain AJAG7, 58 and Bacillus sp. 33 have been studied for the degradation of fipronil.…”

“…It is important to note that, in other published work, the biodegradation of fipronil usually also produced fipronil-sulfide and fipronil-sulfone. 27,32,41 The presence of the other two metabolites 5 is related more to environmental influences.…”

“…29 A few studies have been conducted on fipronil biodegradation. 18,22,[28][29][30][31][32][33][34][35][36][37][38][39][40][41] However, not enough studies have been performed in tropical regions. The purpose of this research is to provide a better understanding of the fipronil biodegradation process and the metabolites generated in tropical soils.…”

New Insights into the Effect of Fipronil on the Soil Bacterial Community

“…Among them, we can mention Bacillus thuringiensis [ 57 ] and Streptomyces rochei [ 58 ]. In the same vein, Cappelini et al [ 59 ] observed that the bacterium Burkholderia thailandensis belonging to the phylum Proteobacteria also showed potential for fipronil degradation. Another example is the result observed by Ahemad et al [ 60 ], where the authors stated that the Rhizobium strain MRL3 could grow in a medium with fipronil as the sole source of carbon and nitrogen.…”

Biodegradation of Fipronil: Transformation Products, Microbial Characterisation and Toxicity Assessment

“…Productivity of sugarcane crops is maintained by soil management, such as addition of organic matter and nutrients, through the use of vinasse and filter cake, maintenance of sugarcane straw on the soil surface, crop rotation, development of new cultivars and use of pesticides (Bordonal et al, 2018). Due to restrictions of the use of organochlorine and organophosphate insecticides, the application of fipronil is increasing (Cappelini et al, 2018). This insecticide is applied in sugarcane plantation as Regent® 800 WG to control Lepidoptera and Orthoptera on crops and Coleoptera larvae in soils.…”