This study aimed to investigate the effect of inoculation with Weissella paramesenteroides NCU031042 and Lactiplantibacillus plantarum NCU001980 on the quality of soy sauce. Three inoculation strategies were evaluated, the analysis results of flavor components and biogenic amine (BA) levels suggested that the optimal strategy for soy sauce fermentation was to inoculate W. paramesenteroides NCU031042 on day 1 (1.0 × 10⁶ CFU/g), and L. plantarum NCU001980 on day 7 (1.0 × 10⁶ CFU/g). This enhanced its organic acids (1.47-fold), volatiles (1.29-fold), and free amino acids (1.21-fold) flavors. It demonstrated a superior 2-methoxy-4-vinylphenol production capacity and characteristic flavor components such as lactic acid, 1-octen-3-ol, benzeneacetaldehyde, and glutamic acid were increased by 1.38-, 1.45-, 4.10-, and 1.37-fold, respectively. Besides, the content of BA was reduced by 42.26%, and most of them were positively correlated with their precursors, suggesting that the addition of W. paramesenteroides NCU031042 and L. plantarum NCU001980 inhibited the growth of microorganisms involved in BA synthesis or degraded them. This work provides valuable information for the exploration and industrial application of functional microorganisms in soy sauce fermentation.

Colorectal cancer (CRC), a highly prevalent and lethal gastrointestinal malignancy, has recently seen growing interest in probiotics for its prevention and treatment. This study evaluated the mitigating effects of Lactiplantibacillus plantarum (NCU0011098, NCUH001084, and NCU0011129) on AOM/DSS-induced CRC mice. Phenotypic indicators and histopathological analysis demonstrated that all three strains improved the survival rates of CRC mice, reduced colonic tumor burden and shortening of colon length, lowered inflammation and oxidative stress levels in the colon, and alleviated intestinal barrier damage. Among them, NCU0011129 demonstrated the most remarkable efficacy, with a 26.19% increase in survival rate compared to the CRC group (66.7%). This strain also improved colon shortening by 68.16%. Furthermore, amplicon sequencing revealed that L. plantarum NCU0011129 ameliorated gut dysbiosis by decreasing the relative abundance of Desulfovibrio, Dubosiella, and Paramuribaculum, while promoting beneficial genera (Akkermansia, Muribaculum, and Alistipes). Notably, L. plantarum NCU0011129 modulated the serum metabolic profiles of CRC mice, altered amino acid and lipid metabolism pathways, with arachidonic acid metabolism being the most significantly affected. Overall, L. plantarum NCU0011129 inhibited CRC progression by modulating gut microbiota and host metabolism, with its efficacy linked to the specific attenuation of the arachidonic acid-inflammatory axis. These findings offer a promising probiotic-based strategy for CRC intervention.

A strain of lactic acid bacteria (LAB) with an inhibitory effect on Staphylococcus aureus was isolated from naturally fermented pickle. The strain was identified as Lactococcus lactis subsp. lactis and named NCU036018 by 16S rDNA gene sequence analysis and physiological and biochemical experiments. The antibacterial substance in the fermentation supernatant of NCU036018 was sensitive to trypsin, papain, protease K and α-chymotrypsin, but not to pepsine, lipase, amylase or catalase, and retained more than 70% and 90% of its activity at pH 2.0–10.0 and 50–100 ℃, respectively. Then, the antibacterial substance was separated and purified by successive steps of ammonium sulfate saltingout, ultrafiltration and cation exchange chromatography. The obtained bacteriocin was named lactococcin 036018, whose molecular mass and minimum inhibitory concentration (MIC) were 14.4-20 kDa and 0.50 mg/mL, respectively. Lactococcin 036018 could effectively reduce the biofilm formation rate of S. aureus, damage the morphology of the cell surface, reduce the permeability of the cell membrane and consequently inhibit or even killing the cells. The bacteriocin had a significant inhibitory effect on the growth of S. aureus in milk, thereby showing great promise as a food preservative.