Optimization of polyethylene terephthalate biodegradation using a self-assembled multi-enzyme cascade strategy

Surface Display Technologies for Whole-Cell Biocatalysts: Advances in Optimization Strategies, Food Applications, and Future Perspectives

Surface display technology has revolutionized whole-cell biocatalysis by enabling efficient enzyme immobilization on microbial cell surfaces. Compared with traditional enzyme immobilization, this technology has the advantages of high enzyme activity, mild process, simple operation and low cost, which thus has been widely studied and applied in various fields. This review explores the principles, optimization strategies, applications in the food industry, and future prospects. We summarize the membrane and anchor protein structures of common host cells (Escherichia coli, Bacillus subtilis, and yeast) and discuss cutting-edge optimization approaches, including host strain genetic engineering, rational design of anchor proteins, innovative linker peptide engineering, and precise regulation of signal peptides and promoters, to maximize surface display efficiency. Additionally, we also explore its diverse applications in food processing and manufacturing, additive synthesis, food safety, and other food-related industries (such as animal feed and PET packaging degradation), demonstrating their potential to address key challenges in the food industry. This work bridges fundamental research and industrial applications, offering valuable insights for advancing agricultural and food chemistry.

Biocatalytic recycling of plastics: facts and fiction

Due to the lack of efficient end-of-life management, the mass production of plastics has resulted in serious environmental problems. Sustainable biological approaches using enzymes to degrade and recycle plastic waste are emerging as a complement to conventional methods to promote a circular economy of plastics. Only a fraction of the plastic waste generated is currently suitable for biocatalytic deconstruction and the development of economically and environmentally competitive processes is still pending. Inconsistent claims about new plastic-degrading enzymes reveal a need for robust and standardized analysis methods to ensure reproducible results and a realistic evaluation of their potential. This paper critically reviews enzymatic synthetic polymer degradation and its recycling challenges.

Customization of Ethylene Glycol (EG)-Induced BmoR-Based Biosensor for the Directed Evolution of PET Degrading Enzymes

The immense volume of plastic waste poses continuous threats to the ecosystem and human health. Despite substantial efforts to enhance the catalytic activity, robustness, expression, and tolerance of plastic-degrading enzymes, the lack of high-throughput screening (HTS) tools hinders efficient enzyme engineering for industrial applications. Herein, we develop a novel fluorescence-based HTS tool for evolving polyethylene terephthalate (PET) degrading enzymes by constructing an engineered BmoR-based biosensor targeting the PET breakdown product, ethylene glycol (EG). The EG-responsive biosensors, with notably enhanced dynamic range and operation range, are customized by fluorescence-activated cell sorting (FACS)-assisted transcription factor engineering. The ingeniously designed SUMO-MHETase-FastPETase (SMF) chimera successfully addresses the functional soluble expression of MHETase in Escherichia coli and mitigates the inhibitory effect of mono-(2-hydroxyethyl) terephthalic acid (MHET) intermediate commonly observed with PETase alone. The obtained SMM3F mutant demonstrates 1.59-fold higher terephthalic acid (TPA) production, with a 1.18-fold decrease in Km, a 1.29-fold increase in Vmax, and a 1.52-fold increase in kcat/Km, indicating stronger affinity and catalytic activity toward MHET. Furthermore, the SMM3F crude extract depolymerizes 5 g L-1 bis-(2-hydroxyethyl) terephthalic acid (BHET) into TPA completely at 37 °C within 10 h, which is then directedly converted into value-added protocatechuic acid (PCA) (997.16 mg L-1) and gallic acid (GA) (411.69 mg L-1) at 30 °C, establishing an eco-friendly 'PET-BHET-MHET-TPA-PCA-GA' upcycling route. This study provides a valuable HTS tool for screening large-scale PET and MHET hydrolases candidates or metagenomic libraries, and propels the complete biodegradation and upcycling of PET waste.

A review on computational models for predicting protein solubility

Protein solubility is a critical factor in the production of recombinant proteins, which are widely used in various industries, including pharmaceuticals, diagnostics, and biotechnology. Predicting protein solubility remains a challenging task due to the complexity of protein structures and the multitude of factors influencing solubility. Recent advances in computational methods, particularly those based on machine learning, have provided powerful tools for predicting protein solubility, thereby reducing the need for extensive experimental trials. This review provides an overview of current computational approaches to predict protein solubility. We discuss the datasets, features, and algorithms employed in these models. The review aims to bridge the gap between computational predictions and experimental validations, fostering the development of more accurate and reliable solubility prediction models that can significantly enhance recombinant protein production.

Icaritin production from Epimedium folium extract by a one-pot enzymatic cascade of a multifunctional glycosidase and rhamnosidase

Icaritin (ICT), a compound with diverse biological activities derived from Epimedium folium, is typically present in low concentrations in EFs. However, the abundant glycosyl-modified ICT compounds facilitate its transformation into ICT. Current biocatalytic production faces challenges, including low conversion rates and limited enzyme activity. This study developed a one-pot enzymatic cascade strategy for directly biotransform crude extracts of Epimedium folium (EEF) to produce ICT. The feasibility of catalyzing different ICT-related compounds in EEF was validated through molecular docking and substrate reactions. The selected glycosidase exhibited simultaneous activities as a glucosidase, xylosidase, and α-1,6-rhamnosidase, with the rhamnosidase showing outer-rhamnosidic activity and weak glucosidase activity. By using EFs as the substrate and employing whole-cells (Escherichia coli) containing LacS and BtRha proteins for synergistic catalysis, icariin can be efficiently synthesized within 6 h, achieving a conversion rate of 100 %. The enzymatic cascade for ICT production from crude extracts was elucidated by analyzing catalytic intermediates via HPLC. Compared to strategies using single or traditional multi-enzyme applications, this method shows advantages of ease to operation, high efficiency, and large production yield performance. This method has the potential to become an eco-friendly catalytic strategy for the large-scale production of icaritin.

Nature-Inspired Strategies for Sustainable Degradation of Synthetic Plastics

Synthetic plastics have become integral to our daily lives, yet their escalating production, limited biodegradability, and inadequate waste management contribute to environmental contamination. Biological plastic degradation is one promising strategy to address this pollution. The inherent chemical and physical properties of synthetic plastics, however, pose challenges for microbial enzymes, hindering the effective degradation and the development of a sustainable biological recycling process. This Perspective explores alternative, nature-inspired strategies designed to overcome some key limitations in currently available plastic-degrading enzymes. Nature's refined degradation pathways for natural polymers, such as cellulose, present a compelling framework for the development of efficient technologies for enzymatic plastic degradation. By drawing insights from nature, we propose a general strategy of employing substrate binding domains to improve targeting and multienzyme scaffolds to overcome enzymatic efficiency limitations. As one potential application, we outline a multienzyme pathway to upcycle polyethylene into alkenes. Employing nature-inspired strategies can present a path toward sustainable solution to the environmental impact of synthetic plastics.