Identification of the key amino acid sites of the carbofuran hydrolase CehA from a newly isolated carbofuran-degrading strain Sphingbium sp. CFD-1

et al. 2021

Front. Microbiol.

Phenol is a toxic organic molecule that is widely detected in the natural environment, even in drinking water sources. Biological methods were considered to be a good tool for phenol removal, especially microbial immobilized technology. However, research on the “seed” bacteria along with microbial community analysis in oligotrophic environment such as drinking water system has not been addressed. In this study, Acinetobacter sp. DW-1 with high phenol degradation ability had been isolated from a drinking water biofilter was used as seeded bacteria to treat phenol micro-polluted drinking water source. Meanwhile, the whole genome of strain DW-1 was sequenced using nanopore technology. The genomic analysis suggests that Acinetobacter sp. DW-1 could utilize phenol via the β-ketoadipate pathway, including the catechol and protocatechuate branches. Subsequently, a bio-enhanced polyhedral hollow polypropylene sphere (BEPHPS) filter was constructed to investigate the stability of the seeded bacteria during the water treatment process. The denatured gradient gel electrophoresis (DGGE) profile and the quantification of phenol hydroxylase gene results indicate that when the BEPHPS filter was operated for 56 days, Acinetobacter sp. was still a persistent and competitive bacterium in the treatment group. In addition, 16S rRNA gene amplicon sequencing results indicate that Acinetobacter sp., as well as Pseudomonas sp., Nitrospira sp., Rubrivivax sp. were the predominant bacteria in the treatment group, which were different from that in the CK group. This study provides a better understanding of the mechanisms of phenol degradation by Acinetobacter sp. DW-1 at the gene level, and provides new insights into the stability of seeded bacteria and its effects on microbial ecology during drinking water treatment.

“…Sphingobium sp. were reported to degrade Bisphenol A ( Jia et al, 2020 ), carbofuran ( Jiang et al, 2020 ) and 17 Archetypal Organophosphate ( Azam et al, 2019 ). Novosphingobium sp.…”

Section: Resultsmentioning

confidence: 99%

Genomic Analysis and Stability Evaluation of the Phenol-Degrading Bacterium Acinetobacter sp. DW-1 During Water Treatment

Chen

et al. 2021

Front. Microbiol.

“…Esterase plays a significant role in the hydrolysis of a wide range of ester-containing xenobiotics. The esterase genes involved in the hydrolysis of several pesticides and herbicides, such as phenmedipham, pyrethroids, parathion, carbaryl, carbendazim, carbofuran, and phenylurea, have been cloned and characterized (29,(36)(37)(38)(39)(40)(41). In this study, StrH was proved to have the ability to hydrolyze strobilurin fungicides.…”

Section: Discussionmentioning

confidence: 99%

Detoxification Esterase StrH Initiates Strobilurin Fungicide Degradation in Hyphomicrobium sp. Strain DY-1

Jiang

Gao

et al. 2021

Appl Environ Microbiol

Self Cite

Strobilurin fungicides are widely used in agricultural production due to their broad-spectrum and fungal mitochondrial inhibitory activities. However, their massive application has detained the growth of eukaryotic algae and increased the collateral damage in freshwater systems, notably the harmful cyanobacterial blooms (HCBs). In this study, a strobilurin fungicide-degrading strain Hyphomicrobium sp. DY-1 was isolated and characterized successfully. Moreover, a novel esterase gene strH responsible for the de-esterification of strobilurin fungicides was cloned, and the enzymatic properties of StrH were studied. For trifloxystrobin, StrH displayed the maximum activity at 50°C and pH 7.0. The catalytic efficiency (kcat/Km) of StrH for different strobilurin fungicides were 196.32±2.30 μM−1·s−1 (trifloxystrobin), 4.64±0.05 μM−1·s−1 (picoxystrobin), 2.94±0.02 μM−1·s−1 (pyraclostrobin), and (2.41±0.19)×10−2 μM−1·s−1 (azoxystrobin). StrH catalyzed the de-esterification of a variety of strobilurin fungicides generating the corresponding parent acid to achieve the detoxification of strobilurin fungicides and relieve strobilurin fungicides growth inhibition on Chlorella. This research will provide insight into the microbial remediation of strobilurin fungicides-contaminated environments. IMPORTANCE Strobilurin fungicides have been widely acknowledged as an essential group of pesticides worldwide. So far, their residues and toxic effects on aquatic organisms have been reported in different parts of the world. Microbial degradation could eliminate xenobiotics from the environment. Therefore, the degradation of strobilurin fungicides by microorganisms has also been reported. However, little is known about the involvement of enzyme or gene in strobilurin fungicides degradation. In this study, a novel esterase gene strH responsible for the detoxification of strobilurin fungicides was cloned in the newly isolated strain Hyphomicrobium sp. DY-1. This degradation process detoxifies the strobilurin fungicides and relieves their growth inhibition on Chlorella.

“…For instance, the chd gene, responsible for cleavage of the carbon‐chlorine bond of chlorothalonil, was found to be highly conserved (99.4%–100%) among the chlorothalonil‐dechlorinating bacterial strains from eight genera ( Bordetella , Pseudomonas , Lysobacter , Pseudoxanthomonas , Caulobacter , Ochrobactrum , Rhizobium and S hinella ) (Liang et al ., 2011; Wang et al ., 2011). The cehA gene, responsible for cleavage of the carbamate ester bond, was found to be highly conserved, varying by only four amino acids among the carbamate‐degrading strains belonging to the genera Novosphingobium , Rhizobium , Sphingomonas and Sphingobium (Hashimoto et al ., 2002; Nguyen et al ., 2014; Yan et al ., 2018; Jiang et al ., 2020). The atzA / trzN genes, responsible for the hydrolytic dechlorination of atrazine to form hydroxyatrazine, were found to be highly conserved among the atrazine‐degrading bacteria belonging to the genera Pseudomonas , Arthrobacter , Nocardioides , Rhizobium , Chelatobacter , Sinorhizobium , Agrobacterium and Polaromonas (Mandelbaum et al ., 1995; Aislabie et al ., 2005; Satsuma, 2010; Smith et al ., 2005; Rousseaux et al ., 2002; Devers et al ., 2007).…”

Section: Discussionmentioning

confidence: 99%

Comparative genomic analysis of iprodione‐degrading Paenarthrobacter strains reveals the iprodione catabolic molecular mechanism in Paenarthrobacter sp. strain YJN‐5

Environmental Microbiology

Ren

Jiang

et al. 2020

Self Cite

Summary Degradation of the fungicide iprodione by the Paenarthrobacter sp. strain YJN‐5 is initiated via hydrolysis of its N1 amide bond to form N‐(3,5‐dichlorophenyl)‐2,4‐dioxoimidazolidine. In this study, another iprodione‐degrading strain, Paenarthrobacter sp. YJN‐D, which harbours the same metabolic pathway as strain YJN‐5 was isolated and characterized. The genes that encode the conserved iprodione catabolic pathway were identified based on comparative analysis of the genomes of the two iprodione‐degrading Paenarthrobacter sp. and subsequent experimental validation. These genes include an amidase gene, ipaH (previously reported in AEM e01150‐18); a deacetylase gene, ddaH, which is responsible for hydantoin ring cleavage of N‐(3,5‐dichlorophenyl)‐2,4‐dioxoimidazolidine, and a hydrolase gene, duaH, which is responsible for cleavage of the urea side chain of (3,5‐dichlorophenylurea)acetic acid, thus yielding 3,5‐dichloroaniline as the end product. These iprodione‐catabolic genes are distributed on three plasmids in strain YJN‐5 and are highly conserved between the two iprodione‐degrading Paenarthrobacter strains. However, only the ipaH gene is flanked by a mobile genetic element. Two iprodione degradation cassettes bearing ipaH‐ddaH‐duaH were constructed and expressed in strains Pseudomonas putida KT2440 and Bacillus subtilis SCK6 respectively. Our findings enhance the current understanding of the microbial degradation mechanism of iprodione.