Understanding Fabric Yellowing: Insights into Microbial Interactions and Human Secretions

Fabric yellowing by germ stains affects the aesthetics and durability of fabrics. Herein, two chromogenic strains were isolated and identified from yellowing fabrics: Pantoea calida FY1 ( P. calida FY1) and Pseudomonas luteola FY2 ( P. luteola FY2). Notably, 16S rRNA high-throughput sequencing identified Pantoea and Pseudomonas as the predominant genera in these yellowing fabrics, prompting the focus on these chromogenic strains. Both strains were verified to cause yellowing of brand-new fabrics. After adding human secretions, the fabric yellowing caused by the strains intensified. Quantitative research on multiple factors (sweat, sebum, and chromogenic strains) indicated that the degree of yellowing on the fabric surface due to the combined action of two strains was higher than that caused by P. calida FY1 or P. luteola FY2 alone, with the yellowing further aggravated by the synergistic effects of sebum and sweat. Among them, the yellowing ability ranked as follows: P. calida FY1 + P. luteola FY2 > P. luteola FY2 > P. calida FY1 > sweat > sebum. Furthermore, four molecules with color-emitting groups, including palmitic acid, dibutyl phthalate, phthalic anhydride, and 4,5-dichloro-2H-octyl-3(2H)-isothiazolone, were obtained from both the metabolites of the chromogenic strains and the coloring substances on fabric surfaces using liquid chromatography tandem mass spectrometry (LC-MS/MS), implying a potential role of the molecules in inducing yellowing. These results suggest that fabric yellowing is closely related to the presence of chromogenic microorganisms on the fabric surface and their metabolites, thereby providing a mechanistic foundation that is crucial for sustainable textile engineering.