Screening and identification of predominant nitrite-degrading lactic acid bacteria from southern Anhui pickles and their application in vegetable fermentation

The rising demand for nitrite-free fermented vegetables necessitates novel starter cultures. Forty-two lactic acid bacteria (LAB) were isolated and purified from pickled vegetables collected in southern Anhui Province by pure culture. Five strains of LAB (Strains 6-2, 13-1, 2-2, Q3, and 5-3) with a strong ability to degrade nitrate were detected. When applied to kale fermentation, these strains demonstrated superior performance compared to natural fermentation, achieving rapid acidification (pH ≤ 3.6 within 48 h), high titratable acid content (0.68% within 120 h), efficient nitrite reduction (residual nitrite ≤ 0.3 mg kg −1 vs 13.3 mg kg −1 in controls), and robust viable cell counts (>4.77 log CFU g −1 ). The major representative of the LAB named Q3 involved in these fermentations was identified as Lactiplantibacillus plantarum (GenBank accession number MT482751). This study not only demonstrates the biotechnological potential of traditional pickle-derived LAB but also provides a scientific foundation for developing starter cultures that simultaneously ensure rapid acid production, effective nitrite removal, and microbial stability in vegetable fermentation systems.