Selenium-enriched Bacillus siamensis and Staphylococcus arlettae isolated from fermented rice

Abstract

Selenium-enriched probiotics offer a promising strategy to combat oxidative stress and enhance gut health due to their antioxidant and immune-modulating properties. However, limited studies have explored selenium biofortification in non-conventional strains isolated from traditional Indian fermented foods. To address the research gap, this study aimed to isolate and characterize selenium-enriched probiotic strains from koozh, a naturally fermented rice-based product widely consumed in southern India. Bacterial strains were isolated from three fermented rice samples, enriched with selenium, and identified using 16S ribosomal RNA gene sequencing. Selenium uptake was quantified through atomic absorption spectroscopy, and probiotic potential was assessed based on tolerance to acidic pH, bile salts, and carbohydrate fermentation capacity. Among 20 isolates screened, Bacillus siamensis and Staphylococcus arlettae exhibited strong survival under gastrointestinal conditions and selenium-enrichment ability. Notably, S. arlettae showed the highest selenium uptake efficiency, marking it as a strong candidate for functional food development. These findings highlight the potential of selenium-enriched probiotics derived from traditional fermented foods as novel bioactive ingredients in fortification strategies aimed at promoting gut health and antioxidant defense.