Novel insights into p-cresol production in fermented bamboo shoots: Core microbiota and metabolic signatures

p -Cresol has been identified as a key odorant that is responsible for the characteristic flavor of fermented bamboo shoots. Although it is known to play a significant role in bamboo shoot fermentation, the microbial sources and biosynthetic pathways of p -cresol is still poorly characterized. The relationship between the microbiota and flavor profiles in fermented bamboo shoots was systematically investigated in this study via metagenomics and gas chromatography–mass spectrometry (GC–MS). The results demonstrated that Lactobacillus and Kazachstania represented the dominant microbial genera, with Lactobacillus acetotolerans identified as the most abundant bacterial species. Phenols and acids were identified as the primary flavor components, and p -cresol was found to be the dominant flavor compound. Correlation analysis was further found to reveal significant positive associations between specific microorganisms (e.g., L. acetotolerans ) and key flavor compounds (including p- cresol). The formation of the main characteristic flavors in fermented bamboo shoots was closely associated with carbohydrate and amino acid metabolism pathways. Tyrosine was first converted to 4-hydroxyphenylacetate via transamination, followed by subsequent decarboxylation to p -cresol catalyzed by the enzyme 4-hydroxyphenylacetate decarboxylase. This study provides insights into the microbial mechanisms underlying the formation of the stinky flavor in fermented bamboo shoots.