Reclamation of the Lianhua-Qingwen Residue as Functional Feed Additives Processed by a Designed Precise Fermentation

Lianhua-Qingwen (LHQW) stands as a compound herbal remedy renowned for its efficacy in addressing pandemic viral ailments like COVID-19. The production of LHQW capsules, however, generates substantial residues, contributing to environmental strain and resource squandering. To counteract this, we have devised a meticulously orchestrated co-fermentation approach, christened as “precise fermentation, PF”. This entails a well-coordinated interplay of enzyme, Saccharomyces , and Lactobacillus under precisely controlled temperatures, designed to maximize the utilization of these remnants as invaluable feed additives. The genesis of PF involves an initial phase of sterile liquid-state fermentation (LF) of the residues. This expeditiously establishes the suitability of the evaluated microbial agents, with Lactobacillus plantarum SK3494 and Saccharomyces cerevisiae emerging as the most promising candidates based on criteria including viable cell number, pH, reducing sugar (RS) and protein contents. Subsequent to this, a sterile solid-state fermentation (SF) of the residues was executed, evaluating the degradation potency of a high-temperature-tolerant enzyme blend, Aspergillus niger , and Bacillus subtilis. This investigation revealed the rapid and bountiful liberation of RS through the enzyme cocktail treatment. Guided by these insights, a SF-based PF was formulated under unsterile conditions, structured as follows: (1) enzyme cocktail-mediated soluble sugar release (0.5%, 50 °C, 2 days); (2) S. cerevisiae (10 6 CFU/g, 30 °C, 1 days); (3) L. plantarum (10 6 CFU/g, 40 °C, 4 days)-based medicinally active metabolites enrichment. In a comprehensive evaluation, PF outperformed spontaneous fermentation (SF) and other conventional methods for disposing of medicinal herbal residues (MHR). This superiority is reflected in heightened concentrations of total sugar, RS, total antioxidant activity, and total polyphenol content. Furthermore, PF yielded an enrichment of flavonoids such as tectoridin, tricetin, isorhamnetin, apigenin, naringenin, and more. The present study introduces and elucidates the concept of precise fermentation, marking a pioneering advancement in the comprehensive utilization of MHR for augmenting feed supplements. Graphical Abstract