Moonlighting proteins are those capable of performing more than one biochemical or biophysical function within the same polypeptide chain. They have been a recent focus of research due to their potential applications in the health, pharmacological, and nutritional sciences. Among them, some ribosomal proteins involved in assembly and protein translation have also shown other functionalities, including inhibiting infectious bacteria, viruses, parasites, fungi, and tumor cells. Therefore, they may be considered antimicrobial peptides (AMPs). However, information regarding the mechanism of action of ribosomal proteins as AMPs is not yet fully understood. Researchers have suggested that the antimicrobial activity of ribosomal proteins may be associated with an increase in intracellular reactive oxidative species (ROS) in target cells, which, in turn, could affect membrane integrity and cause their inactivation and death. Moreover, the global overuse of antibiotics has resulted in an increase in pathogenic bacteria resistant to common antibiotics. Therefore, AMPs such as ribosomal proteins may have potential applications in the pharmaceutical and food industries in the place of antibiotics. This article provides an overview of the potential roles of ribosomes and AMP ribosomal proteins in conjunction with their potential applications.

This review critically analyzes bioactive compounds derived from agro-industrial by-products, including polyphenols, natural pigments, dietary fiber, prebiotics, lipids, proteins, and bioactive peptides. The review examines their chemical characteristics, major agro-industrial sources, and recovery strategies, highlighting both conventional technologies and emerging green technologies, such as ultrasound-assisted extraction, supercritical fluids, and natural deep eutectic solvents (NADESs). Across compound classes, common patterns are identified, including the importance of external plant tissues as primary biological reservoirs, as well as a methodological convergence in extraction processes despite the wide chemical diversity of the molecules. Shared challenges related to compound stability, scalability, and process efficiency are also discussed. The results demonstrate that agro-industrial by-products should be understood as complex, integrated matrices rather than isolated sources of individual compounds, thereby supporting the development of unified biorefinery schemes. Unlike previous reviews focused on individual compound classes, this review integrates multiple classes of bioactive compounds, green extraction technologies, analytical characterization strategies, and industrial valorization approaches within a circular biorefinery framework. In conclusion, this review helps bridge the current fragmented understanding of waste valorization and highlights key opportunities for the sustainable development of high-value-added functional ingredients within the framework of the circular economy.

The growing challenge of antibiotic resistance has intensified the search for new antimicrobial agents. Promising alternatives include peptidoglycan hydrolases (PGHs) and certain ribosomal proteins, both of which exhibit antimicrobial activity. This study focuses on a Lactiplantibacillus paraplantarum strain, isolated from fermented meat, capable of inhibiting pathogens such as Listeria innocua, Salmonella Typhimurium, Escherichia coli, Staphylococcus aureus, and Weissella viridescens. The highest growth and antimicrobial activity were observed at a high nitrogen concentration (5.7 g/L). Two antimicrobial proteins were identified: the 50S ribosomal protein L14 (RP uL14) and 6-phospho-N-acetylmuramidase (MupG), a PGH. Partial purification and characterization of these proteins were achieved using SDS-PAGE, zymography, and LC-MS/MS. Transcriptional data (RT-qPCR) showed that higher nitrogen concentrations enhanced MupG expression, while increased carbon concentrations boosted RP uL14 expression. These findings highlight the importance of nutritional sources in maximizing the production of novel antimicrobial proteins, offering a potential path to develop effective alternatives against antibiotic-resistant bacteria.