Siderophores are a class of small molecules renowned for their high iron binding capacity, essential for all life forms requiring iron. This article provides a detailed review of the diverse classifications, and biosynthetic pathways of siderophores, with a particular emphasis on siderophores synthesized via nonribosomal peptide synthetase (NRPS) and non-NRPS pathways. We further explore the secretion mechanisms of siderophores in microbes and plants, and their role in regulating bioavailable iron levels. Beyond biological functions, the applications of siderophores in medicine, agriculture, and environmental sciences are extensively discussed. These applications include biological pest control, disease treatment, ecological pollution remediation, and heavy metal ion removal. Through a comprehensive analysis of the chemical properties and biological activities of siderophores, this paper demonstrates their wide prospects in scientific research and practical applications, while also highlighting current research gaps and potential future directions.

Edible powders are important food ingredients, and their quality strongly affects processability, stability, and nutrient delivery. Compared with conventional grinding, superfine grinding enables particle-size reduction to the micron or submicron scale and has shown considerable potential for improving the physicochemical and functional properties of food powders. This review summarizes five representative superfine grinding technologies and discusses how different mechanical force fields regulate powder quality through changes in particle size, specific surface area, cell-wall integrity, and macromolecular structure. Current evidence indicates that superfine grinding can improve hydration behavior, dissolution, the release of bioactive compounds, antioxidant activity, and in vitro bioaccessibility, but these effects are highly dependent on raw-material characteristics and processing conditions. At the same time, excessive micronization may induce particle agglomeration, thermal degradation of sensitive components, sensory deterioration, high energy consumption, and potential safety concerns related to ultrafine particles. Therefore, the performance of a single grinding technology is often constrained by intrinsic physicochemical and engineering limitations. Recent studies suggest that combining superfine grinding with pretreatment, interfacial stabilization, or encapsulation strategies can improve powder stability and functionality more effectively than grinding alone. Future research should focus on standardized evaluation systems, mechanistic clarification across food matrices, and integrated process design for industrial application.

Soil salinization and selenium (Se) deficiency threaten global food security. This study developed a composite bioinoculant combining ACC deaminase-producing Serratia liquefaciens and biogenically synthesized nano-selenium (SeNPs) to alleviate saline–alkali stress and enhance Se nutrition in rice (Oryza sativa L.). A strain of S. liquefaciens with high ACC deaminase activity was isolated and used to biosynthesize SeNPs with stable physicochemical properties. Pot experiments showed that application of the composite inoculant (S3: S. liquefaciens + 40 mmol/L SeNPs) significantly improved seedling biomass (fresh weight +53.8%, dry weight +60.6%), plant height (+31.6%), and root activity under saline–alkali conditions. S3 treatment also enhanced panicle weight, seed-setting rate, and grain Se content (234.13 μg/kg), meeting national Se-enriched rice standards. Moreover, it increased rhizosphere soil N, P, and K availability and improved microbial α-diversity. This is the first comprehensive demonstration that a synergistic bioformulation of ACC deaminase PGPR and biogenic SeNPs effectively mitigates saline–alkali stress, enhances soil fertility, and enables safe Se biofortification in rice.