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).