Screening and mining efficient polyethylene terephthalate (PET)-degrading enzyme is a promising strategy for plastic waste treatment and recycling. This invention provides a novel transcription factor-based biosensor method for identifying potential PET-degrading enzymes from the microorganisms. When PET is degraded by a specific enzyme to produce terephthalic acid (TPA), the transcription factor TphR recognizes the TPA substrate and then activates the transcription of downstream green fluorescent protein (GFP) reporter, generating measurable fluorescence signals in bacterial cells.

Tetracycline antibiotics (TCs) are widely used in medicine, agriculture, and animal husbandry. However, their overuse has led to environmental pollution, posing a significant threat to water sources, soil, and food safety. Therefore, there is an urgent need for efficient, sensitive, simple, and low-cost detection methods for environmental pollution monitoring. In this study, the catalytic activity of copper-based nanozymes was regulated by AAs. Lysine, aspartic acid, glycine, and arginine were chosen as ligands to synthesize different copper-based nanozymes. The results showed that the type of amino acid significantly influenced the particle size, morphology, and peroxidase (POD)-like catalytic activity of Cu2O. Based on these amino acid-regulated Cu2O nanozymes, we further developed a highly sensitive, easy-to-use, and low-cost colorimetric sensor array that can effectively distinguish TCs. This sensor array was successfully validated in binary mixtures and wastewater environments. This study not only provides important insights into the small-molecule regulation of copper-based nanozyme catalytic performance but also offers a novel approach for the detection of TCs in environmental monitoring.

Plastic waste management is challenged by the inefficiencies and environmental impact of traditional chemical recycling methods. Here, the authors explore the chemoenzymatic cascade depolymerization approach, which offers a promising and sustainable solution for transforming plastic waste into valuable products.

The continued growth in phthalate esters (PAEs) production (∼8 million tons per year) has led to the increased emissions of PAEs into atmospheric, soil, and aquatic environments, posing a serious threat to human and animal health. Microbial enzyme-mediated degradation is an effective remediation strategy for removing PAE contaminants in the environment. Several hydrolases from both culturable and non-culturable microorganisms have been identified with outstanding degradation capacities against PAEs. A hydrolase identified from Glutamicibacter sp. strain 0426 could completely degrade 300 mg/L of dibutyl phthalate (DBP) within 12 h at 32℃ and pH 6.9, and an esterase which was screened from a metagenomic library exhibited high hydrolytic activity (128 U/mg) toward DBP at 40℃ and pH 7.5. However, there are still only a limited number of PAE-degrading enzymes that have been fully characterized so far. Herein, we show the significant influence of PAEs on plastic recycling and environmental pollution. We review recent advances in the identification and isolation of PAE-degrading enzymes from diverse environments. We highlight the potential of metagenomic analyses for exploring novel and powerful PAE hydrolases. Moreover, we discuss a possible enzyme-catalyzed reaction mechanism for PAE hydrolysis given the scarce experimental evidence. The substrate specificity among different monoalkyl/dialkyl PAE hydrolases is attributed to the steric hindrance and electrostatic repulsion affecting the PAE binding to an enzyme. Furthermore, we discuss different directed evolution strategies for improving the performance of PAE-degrading enzymes. Several challenges and future directions in research on PAE-degrading enzymes are also identified.

Environmental accumulation of polyamide (nylon) waste is a pressing global issue. Microbial enzyme-mediated biodegradation serves as the most attractive and eco-friendly approach for the sustainable management of end-of-life nylons. However, it is hampered by inefficient degradation rates and a limited knowledge of potential enzymes and mechanisms. Given its significance, this review aims to provide a comprehensive overview of the advancements in enzymatic nylon depolymerization, their mechanisms, their challenges, and their opportunities. The review can then inform protein engineering and enhance the discovery of novel nylon-degrading enzymes.

Global plastic production is increasing yearly, with packaging materials and disposable plastics accounting for a sizable portion of the total. Despite its apparent advantages, the resulting plastic waste accumulates in landfills and oceans, causing severe environmental and public health issues. Shifting from conventional plastics to biodegradable plastics (BPs) is increasingly being proposed as an efficient management of end-of-life plastics. While several BPs such as poly(lactic acid), poly(epsilon-caprolactone), and poly(hydroxyalkanoates) have been widely used, their biodegradation rates often do not meet the anticipated level under home-compost or other certain environments (e.g., soil, marine). Recently, enzyme-embedded BPs have emerged as an outstanding alternative to currently used synthetic plastics. It achieves rapid degradation and compostability by introducing a specific enzyme into the biodegradable polymer. In this context, this review aims to summarize the recent advances in the development of such superior biomaterials. It identifies and prioritizes the critical success factors required for the production of enzyme-embedded BPs. The review also discusses several challenges in the development and application of these innovative polymer materials.

The alarming rise of antibiotic-resistant Gram-negative bacteria poses a global health crisis. Their unique outer membrane restricts antibiotic access. While diffusion porins are well-studied, the role of BON domain-containing proteins (BDCPs) in resistance remains unexplored. We analyze protein databases, revealing widespread BDCP distribution across environmental bacteria. We further describe their conserved core domain structure, a key for understanding antibiotic transport. Elucidating the genetic and biochemical basis of BDCPs offers a novel target to combat antibiotic resistance and restore bacterial susceptibility to antibiotics.