Antimicrobial Enzymes and Proteins: Modes of Action Against Microbes and Microbial Biofilms

Abstract

Antimicrobial enzymes are naturally occurring or engineered biocatalysts that play a crucial role in innate immunity by inhibiting, disrupting, or eliminating pathogenic microorganisms, including bacteria, fungi, and viruses. These enzymes have emerged as promising alternatives to conventional antibiotics because they are broad-spectrum, biodegradable, specific, and less likely to induce resistance. This review explores major classes of antimicrobial enzymes, including lysozyme, lactoperoxidase, lactoferrin, and defensins, and highlights their structures, biological significance, mechanisms of action, and practical applications. Lysozyme hydrolyzes peptidoglycan in bacterial cell walls, while lactoperoxidase generates hypothiocyanite with potent antimicrobial activity. Lactoferrin exerts antimicrobial effects by sequestering iron and disrupting membranes, whereas defensins destroy pathogens by forming pores in microbial membranes and modulating host immunity. The review also examines the diverse mechanisms by which these enzymes combat microorganisms, including cell wall degradation, membrane disruption, biofilm degradation, nucleic acid destruction, nutrient deprivation, and induction of oxidative stress. The review particularly emphasizes their role in overcoming antimicrobial resistance, as antimicrobial enzymes can target resistant pathogens, disrupt biofilms, and enhance the efficacy of conventional antibiotics. The review also discusses their applications in healthcare, food preservation, agriculture, environmental management, industrial processing, and biotechnology. Advances in protein engineering, nanotechnology, synthetic biology, and enzyme formulation have expanded the potential of antimicrobial enzymes and improved their stability and effectiveness. Despite challenges related to production costs, stability, and large-scale implementation, continued research and technological innovation are expected to overcome these limitations. Overall, antimicrobial enzymes are versatile, sustainable antimicrobial agents with significant potential to address emerging microbial threats and contribute to the global fight against antimicrobial resistance.