AMB Express invites articles on the design, engineering, and application of biocatalysts across industrial, environmental, and biomedical biotechnology. This collection covers the full development pipeline of enzyme-based catalysts, from discovery and rational, semi-rational, and computational design, through directed evolution and machine-learning-guided engineering, to immobilisation, whole-cell and cell-free systems, and multi-enzyme cascades. The emphasis is on bioprocesses that deliver real-world performance, spanning the engineering of enzymes for the manufacture of value-added chemicals and pharmaceuticals, the development of robust biocatalysts for bioremediation and waste valorisation, and the design of therapeutic and diagnostic enzymes for biomedical use.

Biocatalysts are central to the transition toward a sustainable, bio-based economy. Enzymes offer selectivity, mild reaction conditions, and renewable feedstock compatibility that conventional chemical catalysis often cannot match, and advances in protein engineering have dramatically expanded the range of reactions and conditions that biocatalysts can tolerate. In industrial biotechnology, engineered enzymes and whole-cell systems underpin the production of fine chemicals, pharmaceutical intermediates, and food and feed ingredients. In environmental biotechnology, tailored biocatalysts drive the degradation of pollutants and plastics, the treatment of wastewater, and the capture and conversion of CO₂. In biomedical biotechnology, engineered enzymes serve as therapeutics, biosensing elements, and diagnostic tools.

This progress has accelerated with the maturation of computational design, structure- and sequence-guided engineering, and artificial intelligence approaches to enzyme discovery. Equally important are the bioprocess innovations, including enzyme immobilisation, continuous-flow biocatalysis, cofactor regeneration, and cascade design, that translate engineered catalysts into viable manufacturing routes. This collection seeks to bridge molecular-level design with applied bioprocess development, and welcomes original research and reviews on all aspects of biocatalyst engineering and its applications.

Topics of interest include, but are not limited to:

• Rational, semi-rational, and computational enzyme design
• Directed evolution and high-throughput screening of enzyme variants
• Machine-learning- and AI-guided enzyme discovery and optimisation
• Enzyme immobilisation and carrier design for improved stability and reusability
• Whole-cell biocatalysis and cell-free enzymatic systems
• Multi-enzyme cascades and pathway engineering for biotransformation
• Biocatalysis for industrial production of chemicals, pharmaceuticals, and fine chemicals
• Biocatalysts for bioremediation, pollutant and plastic degradation, wastewater treatment, and CO₂ conversion
• Therapeutic enzymes, biosensors, and diagnostic applications
• Bioprocess development, scale-up, and continuous-flow biocatalysis

This collection supports and amplifies research related to SDG 6 (Clean Water and Sanitation), SDG 9 (Industry, Innovation & Infrastructure), and SDG 12 (Responsible Consumption & Production).

AMB Express invites articles on quorum sensing in microbial biotechnology. This collection covers fundamental and applied studies of bacterial cell–cell signaling via autoinducers, highlighting their biotechnological implications. Topics of interest include regulation of the production of value-added compounds (metabolites, enzymes, pigments), regulation of biofilm formation, implications in virulence, development of quorum sensing-based biosensors and synthetic biology applications for microbial production, and environmental uses such as bioremediation and wastewater treatment.

Quorum sensing is a fascinating cell-to-cell communication process that microorganisms use to coordinate their behavior based on population density. They achieve this by producing and detecting signaling molecules called autoinducers. In microbial biotechnology, quorum sensing plays a significant role in various applications, and manipulating it offers exciting possibilities. Some of the most notable applications in recent times include: Understanding and controlling biofilms in industrial and medical settings, controlling industrial fermentations, modulating virulence in pathogens, developing novel biosensors, enhancing bioproduction of metabolites and enzymes, and applications in environmental Biotechnology, such as wastewater treatment and bioremediation.

This collection welcomes contributions on all aspects of quorum sensing in microbes and biotechnology. Topics may span fundamental quorum sensing mechanisms and applied manipulation strategies.

Topics of interest include, but are not limited to:

• Mechanisms of quorum sensing and diversity of signaling molecules.

• Quorum sensing in the production of value-added compounds

• Quorum sensing in biofilm formation and strategies for biofilm control.

• Quorum sensing in microbial communities, intraspecies and interspecies cross-talk

• Quorum sensing-regulated virulence and anti-virulence approaches.

• Synthetic biology and metabolic engineering using quorum sensing.

• Quorum sensing-based biosensors and diagnostic tools.

• Environmental biotechnology applications of quorum sensing.

This collection supports and amplifies research related to SDG 6 (Clean Water and Sanitation).