Atrazine biodegradation in soil by Aspergillus niger

Cations impact the biodegradation of iodosulfuron-methyl herbicidal ionic liquids by fungi

In the framework of this study, six fungal isolates which demonstrated a high capability for biodegrading iodosulphuron-methyl sodium as well as herbicidal ionic liquids based on this herbicide were isolated from different soil samples. The isolates were identified based on the ITS region, whereas biodegradation residues were determined based on LC-MS/MS. Depending on the isolate, the half-lives values of the biodegraded herbicide or herbicidal ionic liquid ranged significantly from just 1.25 days to more than 40 days. The research findings unveiled that the structure of cations is a central limiting factor affecting fungal growth and herbicide transformation in case of ionic liquids. The length of the alkyl chain has been identified as the primary driver of herbicide toxicity, emphasizing the importance of structural factors in herbicide design. In cases when dodecyl(2-hydroxyethyl)dimethyl cation was used, its biodegradation ranged from 0 to approx. 20% and the biodegradability of the iodosulfuron-methyl was notably limited for the majority of the studied isolates. This knowledge provides guidance for development and selection of herbicides with reduced environmental impact. This study highlights the ecological importance of soil fungi, their potential role in herbicide biodegradation, the influence of cations on fungal growth and herbicide transformation, and the structural factors governing herbicide toxicity. Further research in these areas may lead to more efficient and environmentally friendly approaches to herbicide management.

Microbiology and Biochemistry of Pesticides Biodegradation

Pesticides are chemicals used in agriculture, forestry, and, to some extent, public health. As effective as they can be, due to the limited biodegradability and toxicity of some of them, they can also have negative environmental and health impacts. Pesticide biodegradation is important because it can help mitigate the negative effects of pesticides. Many types of microorganisms, including bacteria, fungi, and algae, can degrade pesticides; microorganisms are able to bioremediate pesticides using diverse metabolic pathways where enzymatic degradation plays a crucial role in achieving chemical transformation of the pesticides. The growing concern about the environmental and health impacts of pesticides is pushing the industry of these products to develop more sustainable alternatives, such as high biodegradable chemicals. The degradative properties of microorganisms could be fully exploited using the advances in genetic engineering and biotechnology, paving the way for more effective bioremediation strategies, new technologies, and novel applications. The purpose of the current review is to discuss the microorganisms that have demonstrated their capacity to degrade pesticides and those categorized by the World Health Organization as important for the impact they may have on human health. A comprehensive list of microorganisms is presented, and some metabolic pathways and enzymes for pesticide degradation and the genetics behind this process are discussed. Due to the high number of microorganisms known to be capable of degrading pesticides and the low number of metabolic pathways that are fully described for this purpose, more research must be conducted in this field, and more enzymes and genes are yet to be discovered with the possibility of finding more efficient metabolic pathways for pesticide biodegradation.

Investigation of the Persistence, Toxicological Effects, and Ecological Issues of S-Triazine Herbicides and Their Biodegradation Using Emerging Technologies: A Review

S-triazines are a group of herbicides that are extensively applied to control broadleaf weeds and grasses in agricultural production. They are mainly taken up through plant roots and are transformed by xylem tissues throughout the plant system. They are highly persistent and have a long half-life in the environment. Due to imprudent use, their toxic residues have enormously increased in the last few years and are frequently detected in food commodities, which causes chronic diseases in humans and mammals. However, for the safety of the environment and the diversity of living organisms, the removal of s-triazine herbicides has received widespread attention. In this review, the degradation of s-triazine herbicides and their intermediates by indigenous microbial species, genes, enzymes, plants, and nanoparticles are systematically investigated. The hydrolytic degradation of substituents on the s-triazine ring is catalyzed by enzymes from the amidohydrolase superfamily and yields cyanuric acid as an intermediate. Cyanuric acid is further metabolized into ammonia and carbon dioxide. Microbial-free cells efficiently degrade s-triazine herbicides in laboratory as well as field trials. Additionally, the combinatorial approach of nanomaterials with indigenous microbes has vast potential and considered sustainable for removing toxic residues in the agroecosystem. Due to their smaller size and unique properties, they are equally distributed in sediments, soil, water bodies, and even small crevices. Finally, this paper highlights the implementation of bioinformatics and molecular tools, which provide a myriad of new methods to monitor the biodegradation of s-triazine herbicides and help to identify the diverse number of microbial communities that actively participate in the biodegradation process.

Insights of microbial community evolution under benzisothiazolinone exposure in different soil environments

Benzisothiazolinones (1, 2-benzisothiazoline-3-one; BIT) is widely used to control bacterial and fungal diseases of various crops, and their residues in soil may play an important role in the interaction between soil microorganisms. We studied microbial remediation in five representative soils under different soil conditions (unsterilized, sterilized and flooded) using 16S rRNA gene sequencing to investigate the effect of microorganisms on the degradation of BIT residues in soils to minimize the potentially toxic effects of BIT. High-throughput sequencing data showed that the structure and abundance of bacterial communities in BIT soils changed greatly, which might affect their degradation pathways, while Principal Coordinates Analysis (PCoA) results showed that there was no significant difference in the fungal community in different treatments of the five soils, but the degradation rate of BIT was more influenced by anaerobic microorganisms. Furthermore, Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria, and Acidobacteria were the predominant bacterial phyla, accounting for 93.74% of all OTUs, which played an important role in the degradation of BIT. Lysinibacillus had a high relative abundance (21.10%) under flooded treatment conditions in Jilin soil, and its bioremediation may be a reason for the rapid degradation of BIT in flooded treatment. Besides, only soil organic matter (SOM) and pH among the soil properties had significant effects on the microbial community. Based on the further analysis of bacterial phenotype, some microorganisms related to the biodegradation of BIT were found, mainly belonging to Proteobacteria, Bacteroidetes and Firmicutes. This study provides a useful theoretical basis for the biodegradation of BIT using isolated microorganisms.