Emerging Strategies for the Bioremediation of the Phenylurea Herbicide Diuron

Abstract

Diuron (DUR) is a phenylurea herbicide widely used for the effective control of most annual and perennial weeds in farming areas. The extensive use of DUR has led to its widespread presence in soil, sediment, and aquatic environments, which poses a threat to non-target crops, animals, humans, and ecosystems. Therefore, the removal of DUR from contaminated environments has been a hot topic for researchers in recent decades. Bioremediation seldom leaves harmful intermediate metabolites and is emerging as the most effective and eco-friendly strategy for removing DUR from the environment. Microorganisms, such as bacteria, fungi, and actinomycetes, can use DUR as their sole source of carbon. Some of them have been isolated, including organisms from the bacterial genera Arthrobacter, Bacillus, Vagococcus, Burkholderia, Micrococcus, Stenotrophomonas, and Pseudomonas and fungal genera Aspergillus, Pycnoporus, Pluteus, Trametes, Neurospora, Cunninghamella, and Mortierella. A number of studies have investigated the toxicity and fate of DUR, its degradation pathways and metabolites, and DUR-degrading hydrolases and related genes. However, few reviews have focused on the microbial degradation and biochemical mechanisms of DUR. The common microbial degradation pathway for DUR is via transformation to 3,4-dichloroaniline, which is then metabolized through two different metabolic pathways: dehalogenation and hydroxylation, the products of which are further degraded via cooperative metabolism. Microbial degradation hydrolases, including PuhA, PuhB, LibA, HylA, Phh, Mhh, and LahB, provide new knowledge about the underlying pathways governing DUR metabolism. The present review summarizes the state-of-the-art knowledge regarding (1) the environmental occurrence and toxicity of DUR, (2) newly isolated and identified DUR-degrading microbes and their enzymes/genes, and (3) the bioremediation of DUR in soil and water environments. This review further updates the recent knowledge on bioremediation strategies with a focus on the metabolic pathways and molecular mechanisms involved in the bioremediation of DUR.

Biotransformation of metribuzin under various electron acceptor conditions

“…(2021) reported changes in soil microbial community activity by repeated application of dimethachlor and linuron. Biodegradation of phenylurea herbicide diuron was accomplished by the beta‐oxidation pathway by the soil bacteria (Li et al., 2021). Beta‐ketoadipate pathway was used by Acinetobacter tandoii to degrade phenolic compounds (Van Dexter & Boopathy, 2019; Van Dexter et al., 2019).…”

Molecular Responses and Degradation Mechanisms of the Herbicide Diuron in Rice Crops

“…LOC_Os04g38870 is one of the highest transcription levels whose encoding monooxygenase GF14b is regulated by methyl jasmonate and involved in rice tolerance to abiotic stresses . Transformation of DU to 3,4-dichloroaniline via hydrolase and esterase is well known; however, few studies were reported in plants. In rice, plenty of genes encoding hydrolase and esterase like LOC_Os04g56930 and LOC_Os05g30760 exhibited a positive dose–response relationship with DU levels (Figure ).…”

Fungal assisted bio‐treatment of environmental pollutants with comprehensive emphasis on noxious heavy metals: Recent updates

“…All sorbents had the aptitude to eliminate Cd(II) from wastewater samples, and improved elimination happened when fungal cells were immobilized in comparison to free cells. Cd(II) elimination by free and immobilized fungal biomass on loofa sponge from real wastewater samples is presented in the form of Figure 4a (Ali et al, 2021), where PEN is for ‘free Penicillium chrysogenum ’, PEN‐ILS is for ‘ Penicillium chrysogenum immobilized on loofa sponge’, CEP is for ‘free Cephalotheca foveolata ’, CEP‐ILS is for ‘ Cephalotheca foveolata immobilized on loofa sponge’. Sample (1) was wastewater taken from General Motors Factory in Giza, and sample (2) was wastewater taken from Egyptian Plastic and Electricity Factory in Cairo.…”

“…Similarly, higher efficiency was attained by loofa sponge‐immobilized biomass of C. foveolata in comparison to the free C. foveolata usage, with the elimination of 46.8% and 40.0% of Cd(II), respectively. In the sample 2, greater sorption capacity was provided by the usage of loofa sponge‐immobilized biomass consisting of P. chrysogenum and C. foveolata in comparison to the usage of the free fungal species, where they eliminated 54.2% and 50.0% of Cd(II) in compared to 42.2% and 43.0%, respectively (Ali et al, 2021).…”