Complete genome sequence of Acinetobacter indicus and identification of the hydrolases provides direct insights into phthalate ester degradation

Biodegradation of plasticizers by novel strains of bacteria isolated from plastic waste near Juhu Beach, Mumbai, India

Phthalic acid esters are pivotal plasticizers in various applications, including cosmetics, packaging materials, and medical devices. They have garnered significant attention from the scientific community due to their persistence in ecosystems. The multifaceted aspects of PAEs, encompassing leaching, transformation, and toxicity, underscore their prominence as primary components of anthropogenic waste. In this study, we conducted an extensive investigation to isolate and evaluate bacterial strains with the potential to degrade plasticizers from soil samples collected at JUHU Beach, Mumbai. The degradation capabilities of the isolates were meticulously assessed, and their characterization was performed using established microbiological protocols followed by Sanger dideoxy 16S rRNA sequencing. Four isolates demonstrating notable plasticizer degradation proficiency were subjected to in-depth examinations of their growth dynamics and tolerance thresholds. The biodegradation capabilities of these isolates were evaluated under varying pH, temperature, and plasticizer concentrations. Optimization of degradation rates was achieved through a central composite design experiment. Phenotypic characterization of the isolates was conducted through phylogenetic analysis. The isolates were identified as novel strains belonging to Brevibacillus brevis, Acinetobacter baumannii, Moraxella sp., and Halomonas sp. respectively. The novel isolates were submitted to GenBank with accession numbers OP984197, OQ690115, PP174910, and PP177540 respectively.

Engineering bacterial biocatalysts for the degradation of phthalic acid esters

Phthalic acid esters (PAEs) are synthetic diesters derived from o-phthalic acid, commonly used as plasticizers. These compounds pose significant environmental and health risks due to their ability to leach into the environment and act as endocrine disruptors, carcinogens, and mutagens. Consequently, PAEs are now considered major emerging contaminants and priority pollutants. Microbial degradation, primarily by bacteria and fungi, offers a promising method for PAEs bioremediation. This article highlights the current state of microbial PAEs degradation, focusing on the major bottlenecks and associated challenges. These include the identification of novel and more efficient PAE hydrolases to address the complexity of PAE mixtures in the environment, understanding PAEs uptake mechanisms, characterizing novel o-phthalate degradation pathways, and studying the regulatory network that controls the expression of PAE degradation genes. Future research directions include mitigating the impact of PAEs on health and ecosystems, developing biosensors for monitoring and measuring bioavailable PAEs concentrations, and valorizing these residues into other products of industrial interest, among others.

Exploring the role of microbial proteins in controlling environmental pollutants based on molecular simulation

Molecular simulation has been widely used to study microbial proteins' structural composition and dynamic properties, such as volatility, flexibility, and stability at the microscopic scale. Herein, this review describes the key elements of molecular docking and molecular dynamics (MD) simulations in molecular simulation; reviews the techniques combined with molecular simulation, such as crystallography, spectroscopy, molecular biology, and machine learning, to validate simulation results and bridge information gaps in the structure, microenvironmental changes, expression mechanisms, and intensity quantification; illustrates the application of molecular simulation, in characterizing the molecular mechanisms of interaction of microbial proteins with four different types of contaminants, namely heavy metals (HMs), pesticides, dyes and emerging contaminants (ECs). Finally, the review outlines the important role of molecular simulations in the study of microbial proteins for controlling environmental contamination and provides ideas for the application of molecular simulation in screening microbial proteins and incorporating targeted mutagenesis to obtain more effective contaminant control proteins.