Biodegradation of Pyrethroids by a Hydrolyzing Carboxylesterase EstA from Bacillus cereus BCC01

Abstract

Microbial degradation has been considered as a rapid, green, and cost-effective technique to reduce insecticide pollutions in a contaminated environment. However, the instability and low efficacy of non-indigenous microorganisms hampers their further exploitation when being introduced into a real environmental matrix. In order to overcome the restriction that these functional microorganisms are under, we investigated the optimal conditions to improve the pyrethroid-degrading ability of one previously isolated bacterium Bacillus cereus BCC01, where 9.6% of the culture suspension (with cell density adjusted to OD600 = 0.6) was inoculated into 50 mL media and cultivated at pH 8 and 30 °C, and its metabolic pathway was illuminated by analyzing the main metabolites via gas chromatography mass spectrometry (GC-MS). Most importantly, a key pyrethroid-hydrolyzing carboxylesterase gene estA was identified from the genomic library of strain BCC01, and then expressed in Escherichia coli BL21 (DE3). After purification, the recombinant protein EstA remained soluble, displaying high degrading activity against different pyrethroids and favorable stability over a wide range of temperatures (from 15 °C to 50 °C) and pH values (6.5–9). Therefore, the EstA-associated biodegradation of pyrethroids was determined, which could provide novel insights to facilitate the practical application of B. cereus BCC01 in the microbial detoxification of pyrethroid contamination.

Insight Into Microbial Applications for the Biodegradation of Pyrethroid Insecticides

“…Most of the previous work about pyrethroids is based on bacterial degradation. Bacterial strains from the genera Bacillus , Pseudomonas , Raoultella, Achromobacter , Acidomonas , Brevibacterium , Pseudomonas , Streptomyces , Serratia , Sphingobium , Clostridium, Klebsiella , and Lysinibacillus have been characterized for pyrethroid degradation (Cycoń and Piotrowska-Seget, 2016; Birolli et al, 2019; Hu et al, 2019; Zhao et al, 2019). Fungi also have the potential to degrade wide variety of pesticides (Maqbool et al, 2016).…”

“…Esterase enzymes are often studied for pyrethroid degradation, due to their presence in bacteria, fungi, insect, and human tissues (Liu et al, 2017; Wang et al, 2018; Bai et al, 2019). Different genes with complete open reading frames coding pyrethroid hydrolase/esterase enzymes have been reported in bacterial strains (Hu et al, 2019; Yang et al, 2019).…”

Biodegradation and metabolic pathway of fenvalerate by Citrobacter freundii CD-9

“…Microbial degradation has been considered as a rapid, non-secondary polluting, and low-cost technology and is widely used to reduce pesticide pollution in the environment (Hu et al 2019 ; Huang et al 2020 ). Microbial degradation is mainly achieved by screening and isolating highly efficient degrading strains from pesticide-contaminated soil (Zhan et al 2020 ).…”

Purification and characterization of a novel cypermethrin‐hydrolyzing esterase from Bacillus licheniformis B‐1

“…The results verified that the CY‐degrading enzyme is an esterase. In current studies, pyrethroid‐degrading enzymes from environmental isolates mostly belong to the hydrolase family (Fan et al., 2012; Guo et al., 2009; Hu et al., 2019; Li et al., 2008; Maloney et al., 1993; Ruan et al., 2013; Stok et al., 2004; Tang et al., 2015; Wang et al., 2009; Wei et al., 2013; Zhai et al., 2012), except monooxygenase obtained from Streptomyces sp. (Chen et al., 2013).…”

“…However, the enzyme activity of pyrethroid hydrolase is optimal at pH 6.5 (Liang et al, 2005). And the optimum and stability range of the enzyme are slightly alkaline compared with those of the reported pyrethroiddegrading enzyme (Fan et al, 2012;Hu et al, 2019;Liang et al, 2005;Wang et al, 2009). Temperature is another important factor that significantly influences the degradation ability of enzymes.…”