Quality variation patterns in reclaimed pedunculated filament backfill solution during storage

Reclaimed backfill solution, a process-derived liquid generated during pedunculated filament treatment in tobacco manufacturing, has potential value for resource recovery and process reuse; however, its storage stability and deterioration mechanisms remain unclear. To clarify the quality variation patterns during storage, this study analyzed the microbial community composition at different storage stages by using amplicon high-throughput sequencing, identified differential metabolites and functional pathways via untargeted metabolomics, and monitored quality indicators over time. The results show that: 1) During storage, the dominant bacteria in the backfill liquid were Tuberibacillus, Bacillus, and Lactobacillus, while the dominant fungi were Aspergillus, Sampaiozyma, and Boeremia. The relative abundances and diversities of these dominant genera were closely associated with the storage stage. 2) Fourteen significantly altered metabolites were identified in the backfill liquid, such as docosahexaenoic acid, dihomo-gamma-linolenic acid, 5-heptadecyl-1,3-benzenediol and 3-oxoadipic acid. Among them, fatty acyl compounds accounted for the largest proportion and were significantly enriched in the unsaturated fatty acid biosynthesis pathway. 3) The deterioration of the backfill liquid occurred on the fifth day of storage. After deterioration, the total alkaloid content and pH of the backfill solution increased, while the total sugar content and acid value decreased, and the viscosity change was not obvious. Overall, storage-associated shifts in microbial community structure were closely linked to metabolite variation and quality deterioration in the reclaimed backfill solution, with day 5 identified as the critical turning point for quality decline. This finding provides a reference for the management and quality control of other reclaimed or process-derived plant-based liquid systems.