Enhancing ethyl carbamate reduction in Chinese rice wine: Optimal neutral urease production and immobilization by Staphylococcus hominis strain NU-7

Ethyl carbamate (EC), a carcinogen obtained after the reaction of ethanol and urea, is a health concern in rice wine. S . hominis strain NU-7 isolated from a rice wine facility's wheat koji fermentation room can control urea levels and reduce EC. Optimal fermentation conditions include glucose (3.5 g/L), peptone (2.75 g/L), metal ions (0.1 g/L), urea (10 g/L), and pH7. Immobilized neutral urease enzyme, optimized with sodium alginate (20g/L), calcium chloride (50g/L), glutaraldehyde (5.30g/L), and chitosan (2.5g/L), effectively reduces urea and EC in rice wine. The enzyme maintains stability in pH 4-7 and up to 197.3g/L ethanol. This process reduces urea by 18 mg/L and lowers EC by 119.1 μg/L within 72 h without affecting flavor. S . hominis strain NU-7 offers a practical solution for reducing EC in fermented foods while maintaining flavor and safety. • Staphylococcus hominis NU-7 Isolation in Traditional Rice Wine Fermentation. • Efficient Urea Reduction by Staphylococcus hominis NU-7 in Rice Wine Fermentation. • Robust Acidic Survival of Human Staphylococcus NU-7 Urease through Immobilization. • Enhanced Flavor Formation by S. hominis NU-7 in Rice Wine Fermentation.