Functional and flavour-enhancing properties of Staphylococcus sp. from Napham

Napham, traditional fermented food of the Bodo community in Assam, is produced from tender shoots of Colocasia esculenta and dried fish, and was recently granted Geographical Indication (GI) status. Despite its cultural and nutritional significance, its beneficial microbiota remains insufficiently characterized. This study aimed to identify multifunctional bacterial isolates with both functional and flavor-enhancing properties for use as starter cultures. Forty-eight isolates were screened for Gram reaction, enzymatic activities (protease, lipase, carbohydrate fermentation), and biosafety traits. Four isolates (NAP/1, NAP/2, NAP/3, NAP/4) exhibiting a preliminary phenotypic safety profile based on in vitro screening were evaluated for gastrointestinal stress tolerance traits, including tolerance to acid (pH 2.0), phenol (0.4%), salt (8% NaCl), as well as auto-aggregation capacity and adhesion to chicken crop epithelial cells. Among them, isolate NAP/4 exhibited comparatively higher tolerance, strong adhesion, and high auto-aggregation, and demonstrated a favorable in vitro safety profile, including γ-hemolysis and broad antibiotic susceptibility. In curd and rice beverage models, NAP/4 enhanced sensory qualities and produced diverse flavor volatiles, supporting its candidacy as a multifunctional food-fermenting isolate prior to genomic validation. 16S rRNA sequencing revealed NAP/4 as Staphylococcus sp. (GenBank accession: PQ471484.1). Collectively, these findings highlight NAP/4 as a promising candidate for further genomic evaluation toward potential application in controlled fermentation systems and clean-label formulations. However, whole-genome sequencing and in vivo validation remain essential next steps to confirm safety and functional efficacy at the molecular level.