The mechanisms of lactiplantibacillus plantarum J6-6 against iso-α-acid stress and its application in sour beer production

The tolerance of Lactiplantibacillus plantarum (L. plantarum) to iso-α-acid is critical to sour beer production, and the mechanism of its tolerance to iso-α-acid on cell phenotype is still uncovered. In current study, the tolerance of L. plantarum J6 was enhanced by adaptive laboratory evolution (ALE). And the stress response of L. plantarum J6-6 was analyzed by the changes of intracellular protein, cell membrane fatty acid composition and permeability. The strain J6-6 with iso-α-acid (25 mg/L) displayed an increased unsaturation of fatty acids. The protein involved in glycolysis pathway, nucleotide, amino acid and energy metabolism, would enhance the tolerance of J6-6. In addition, ALE can reduce the damage and improve the viability of iso-α-acid. The application of J6-6 in sour beer can easily control the entire fermentation, with more sweet-sour taste and better flavor. This study provides a well-defined target of easy-to-control sour beer.