Biodegradation of Di (2-Ethylhexyl) Phthalate by a novel Enterobacter spp. Strain YC-IL1 Isolated from Polluted Soil, Mila, Algeria

Interaction between Tetrabromobisphenol A and invertebrates in rigid polyurethane biodegradation: Inhibitory effects, chemical transformation and microbial adaptation

Tetrabromobisphenol A (TBBPA) is a brominated flame retardant widely used in electronic plastics, but its effects on invertebrate-mediated plastic biodegradation remain unclear. This study investigated the impact of TBBPA on the biodegradation of rigid polyurethane (RPU) by Galleria mellonella and Tenebrio molitor larvae, and the effects of both larvae on the chemical transformation of TBBPA. Results showed that TBBPA inhibited the uptake of RPU by both larvae, resulting in a decrease of intestinal protein-like fluorescence intensity, reduced the concentrations of certain metabolic by-products of RPU, and inhibited the growth of RPU degradation related bacteria. Most TBBPA was excreted by both larvae, and a small fraction was transformed into less toxic brominated organic compounds. Sequencing analysis suggested that Enterobacteriaceae, Enterococcus, and non-dominant gut bacteria might play a role in TBBPA degradation. This study provides detailed insights into the interactions involved in the biodegradation of TBBPA-containing RPU by two invertebrate species.

A novel and efficient strategy for the biodegradation of di(2-ethylhexyl) phthalate by Fusarium culmorum

Di(2-ethylhexyl) phthalate (DEHP) is a plasticizer that is used worldwide and raises concerns because of its prevalence in the environment and potential toxicity. Herein, the capability of Fusarium culmorum to degrade a high concentration (3 g/L) of DEHP as the sole carbon and energy source in solid-state fermentation (SSF) was studied. Cultures grown on glucose were used as controls. The biodegradation of DEHP by F. culmorum reached 96.9% within 312 h. This fungus produced a 3-fold higher esterase activity in DEHP-supplemented cultures than in control cultures (1288.9 and 443.2 U/L, respectively). In DEHP-supplemented cultures, nine bands with esterase activity (24.6, 31.2, 34.2, 39.5, 42.8, 62.1, 74.5, 134.5, and 214.5 kDa) were observed by zymography, which were different from those in control cultures and from those previously reported for cultures grown in submerged fermentation. This is the first study to report the DEHP biodegradation pathway by a microorganism grown in SSF. The study findings uncovered a novel biodegradation strategy by which high concentrations of DEHP could be biodegraded using two alternative pathways simultaneously. F. culmorum has an outstanding capability to efficiently degrade DEHP by inducing esterase production, representing an ecologically promising alternative for the development of environmental biotechnologies, which might help mitigate the negative impacts of environmental contamination by this phthalate. KEY POINTS: • F. culmorum has potential to tolerate and remove di(2-ethylhexyl) phthalate (DEHP) • Solid-state fermentation is an efficient system for DEHP degradation by F. culmorum • High concentrations of DEHP induce high levels of esterase production by F. culmorum.

The iPhylo suite: an interactive platform for building and annotating biological and chemical taxonomic trees

Accurate and rapid taxonomic classifications are essential for systematically exploring organisms and metabolites in diverse environments. Many tools have been developed for biological taxonomic trees, but limitations apply, and a streamlined method for constructing chemical taxonomic trees is notably absent. We present the iPhylo suite (https://www.iphylo.net/), a comprehensive, automated, and interactive platform for biological and chemical taxonomic analysis. The iPhylo suite features web-based modules for the interactive construction and annotation of taxonomic trees and a stand-alone command-line interface (CLI) for local operation or deployment on high-performance computing (HPC) clusters. iPhylo supports National Center for Biotechnology Information (NCBI) taxonomy for biologicals and ChemOnt and NPClassifier for chemical classifications. The iPhylo visualization module, fully implemented in R, allows users to save progress locally and customize the underlying R code. Finally, the CLI module facilitates analysis across all hierarchical relational databases. We showcase the iPhylo suite's capabilities for visualizing environmental microbiomes, analyzing gut microbial metabolite synthesis preferences, and discovering novel correlations between microbiome and metabolome in humans and environment. Overall, the iPhylo suite is distinguished by its unified and interactive framework for in-depth taxonomic and integrative analyses of biological and chemical features and beyond.

Improving key gene expression and di-n-butyl phthalate (DBP) degrading ability in a novel Pseudochrobactrum sp. XF203 by ribosome engineering

Di-n-butyl phthalate (DBP) is one of the important phthalates detected commonly in soils and crops, posing serious threat to human health. Pseudochrobactrum sp. XF203 (XF203), a new strain related with DBP biodegradation, was first identified from a natural habitat lacking human disturbance. Genomic analysis coupled with gene expression comparison assay revealed this strain harbors the key aromatic ring-cleaving gene catE203 (encoding catechol 2,3-dioxygenase/C23O) involved DBP biodegradation. Following intermediates identification and enzymatic analysis also indicated a C23O dependent DBP lysis pathway in XF203. The gene directed ribosome engineering was operated and to generate a desirable mutant strain XF203R with highest catE203 gene expression level and strong DBP degrading ability. The X203R removed DBP in soil jointly by reassembling bacterial community. These results demonstrate a great value of XF203R for the practical DBP bioremediation application, highlighting the important role of the key gene-directed ribosome engineering in mining multi-pollutants degrading bacteria from natural habitats where various functional genes are well conserved.

Microbial degradation of contaminants of emerging concern: metabolic, genetic and omics insights for enhanced bioremediation

The perpetual release of natural/synthetic pollutants into the environment poses major risks to ecological balance and human health. Amongst these, contaminants of emerging concern (CECs) are characterized by their recent introduction/detection in various niches, thereby causing significant hazards and necessitating their removal. Pharmaceuticals, plasticizers, cyanotoxins and emerging pesticides are major groups of CECs that are highly toxic and found to occur in various compartments of the biosphere. The sources of these compounds can be multipartite including industrial discharge, improper disposal, excretion of unmetabolized residues, eutrophication etc., while their fate and persistence are determined by factors such as physico-chemical properties, environmental conditions, biodegradability and hydrological factors. The resultant exposure of these compounds to microbiota has imposed a selection pressure and resulted in evolution of metabolic pathways for their biotransformation and/or utilization as sole source of carbon and energy. Such microbial degradation phenotype can be exploited to clean-up CECs from the environment, offering a cost-effective and eco-friendly alternative to abiotic methods of removal, thereby mitigating their toxicity. However, efficient bioprocess development for bioremediation strategies requires extensive understanding of individual components such as pathway gene clusters, proteins/enzymes, metabolites and associated regulatory mechanisms. "Omics" and "Meta-omics" techniques aid in providing crucial insights into the complex interactions and functions of these components as well as microbial community, enabling more effective and targeted bioremediation. Aside from natural isolates, metabolic engineering approaches employ the application of genetic engineering to enhance metabolic diversity and degradation rates. The integration of omics data will further aid in developing systemic-level bioremediation and metabolic engineering strategies, thereby optimising the clean-up process. This review describes bacterial catabolic pathways, genetics, and application of omics and metabolic engineering for bioremediation of four major groups of CECs: pharmaceuticals, plasticizers, cyanotoxins, and emerging pesticides.

Effects of plasticizer Di(2-ethylhexyl) phthalate (DEHP) on the microbiome of the marine sponge Hymeniacidon heliophila

Marine pollution research in the last 15 years focused on an emerging anthropogenic contaminant: plastic debris and more specifically, microplastics. Since, not only its physical impacts on marine invertebrates were studied, but also its additives. Phthalate, a plasticizer commonly found in the ocean and known endocrine disruptor was already observed in different aquatic invertebrates, but few is known about its presence and possible effects in Porifera physiology. Our study aimed to analyze potential shifts in Hymeniacidon heliophila (Desmosponge) microbiome after exposure to Di(2-ethylhexyl) phthalate (DEHP), the most common phthalate found in the ocean, in three different doses for 4 and 24 h. Results indicate that alpha diversity had significantly changed between control and exposed organisms but not in all multicomparisons. Microbial community structure changed after exposure as well although most abundant phyla did not vary along the experiment. The core microbiome between control and each exposed organisms contained the vast majority of total ASVs and a few ASVs were exclusive to each experimental group. After DEHP exposure, microbial classes had significant changes and species with phthalate degradation enzymes were identified in a specifically dose dependent manner pointing to a possible bacterial consortium responsible for the phthalate degradation. The bacterial detoxification activity may lead to H. heliophila resistance during DEHP exposure in polluted environmental conditions.

Adsorption Characterization of Lactobacillus sp. for Di-(2-ethylhexyl) phthalate

Di-(2-ethylhexyl) phthalate (DEHP) is the widely detected plasticizer in foods whose exposure is associated with a myriad of human disorders. The present study focused on identifying Lactobacillus strains with high adsorption potential towards DEHP and further elucidating the mechanism of binding using HPLC, FTIR and SEM. Two strains, Lactobacillus rhamnosus GG and Lactobacillus plantarum MTCC 25,433, were found to rapidly adsorb more than 85% of DEHP in 2 h. Binding potential remained unaffected by heat treatment. Moreover, acid pre-treatment enhanced the DEHP adsorption. Chemical pre-treatments, such as NaIO4, pronase E or lipase, caused reduction in DEHP adsorption to 46% (LGG), 49% (MTCC 25,433) and 62% (MTCC 25,433), respectively, attributing it to cell wall polysaccharides, proteins and lipids. This was also corroborated by stretching vibrations of C = O, N-H, C-N and C-O functional groups. Furthermore, SDS and urea pre-treatment, demonstrated the crucial role of hydrophobic interactions in DEHP adsorption. The extracted peptidoglycan from LGG and MTCC 25,433 adsorbed 45% and 68% of DEHP, respectively, revealing the imperative role of peptidoglycan and its integrity in DEHP adsorption. These findings indicated that DEHP removal was based on physico-chemical adsorption and cell wall proteins, polysaccharides or peptidoglycan played a primary role in its adsorption. Owing to the high binding efficiency, L. rhamnosus GG and L. plantarum MTCC 25,433 were considered to be a potential detoxification strategy to mitigate the risk associated with the consumption of DEHP-contaminated foods.

Application of compost assisted by Fe3O4 nanoparticles in di (2-ethylhexyl) phthalate-contaminated soil remediation: Biostimulation strategy, Soil responses, and RSM/CCD Optimization

Globally, contamination of agricultural soils by phthalate esters (PAEs) caused by direct consumption of plastic mulch films has been confirmed. The most widely used plasticizer is di (2-ethylhexyl) phthalate (DEHP), which is a more recalcitrant endocrine-disrupting chemical (EDC). Because of its low solubility and hydrophobicity, it remains in the soil longer, causes bioaccumulation in agricultural products, and has negative repercussions for food safety. In this study, the performance of kitchen organic waste compost assisted by Fe3O4 nanoparticles in DEHP removal efficiency (%) and soil C:N ratio (two responses) was optimized using Response Surface Methodology (RSM) based on Central Composite Design (CCD) in Design-Expert software (11.0.3.0). Under optimum conditions, a DEHP concentration of 10 mg·kg-1 (dw soil), a retention time of 35 days, an NPs dose of 0.99 g·kg-1 (media), a removal efficiency of 91.6 %, and a soil C:N ratio of 10.5 with a desirability of 0.963 were determined. A quadratic model (P-value <0.0001, adjusted R2 = 0.974 (Y1), 0.943 (Y2)) was used to predict the variables and their interactions. The agricultural soil responses in the treatments amended by compost and Fe3O4 NPs (SCN) showed a significant increase in SOM, TC, TN, AP, K, and Fe nutrients when compared to the control (P < 0.05). After 35 days, in the SC1N3 treatment (DEHP concentration = 10 mg·kg-1, NPs dose =1.2 g·kg-1), with higher DEHP removal efficiency (89.57 %), the C:N:P ratio was equal to 100: 9.75:0.69, and the total microbial colony count was 3.6 × 109 CFU/ml at pH 7.45. The study found that compost nutrients and Fe-based nanoparticle micronutrients can enhance DEHP degradation by stimulating the soil's native microflora. As a result, the synergistic potential of compost and Fe3O4 nanoparticles can be considered a promising, cost-effective, and agri-environmentally friendly approach in the "assisted bioremediation" strategy of DEHP-contaminated soils.

Phthalate esters: occurrence, toxicity, bioremediation, and advanced oxidation processes

Phthalic acid esters are emerging pollutants, commonly used as plasticizers that are categorized as hazardous endocrine-disrupting chemicals (EDCs). A rise in anthropogenic activities leads to an increase in phthalate concentration in the environment which leads to various adverse environmental effects and health issues in humans and other aquatic organisms. This paper gives an overview of the research related to phthalate ester contamination and degradation methods by conducting a bibliometric analysis with VOS Viewer. Ecotoxicity analysis requires an understanding of the current status of phthalate pollution, health impacts, exposure routes, and their sources. This review covers five toxic phthalates, occurrences in the aquatic environment, toxicity studies, biodegradation studies, and degradation pathways. It highlights the various advanced oxidation processes like photocatalysis, Fenton processes, ozonation, sonolysis, and modified AOPs used for phthalate removal from the environment.

Biotechnology-based microbial degradation of plastic additives

Plastic additives are agents responsible to the flame resistance, durability, microbial resistance, and flexibility of plastic products. High demand for production and use of plastic additives is associated with environmental accumulation and various health hazards. One of the suitable methods of depleting plastic additive in the environment is bioremediation as it offers cost-efficiency, convenience, and sustainability. Microbial activity is one of the effective ways of detoxifying various compounds as microorganisms can adapt in an environment with high prevalence of pollutants. The present review discusses the use and abundance of these plastic additives, their health-related risks, the microorganisms capable of degrading them, the proposed mechanism of biodegradation, and current innovations capable of improving the efficiency of bioremediation.