NT-OmpA Bioemulsifier: Structural Insights and Polysaccharide-Mediated Enhancement of its Emulsifying Performance

The recent studies found that NT-OmpA (N-terminally truncated SA01-OmpA) has distinct advantages over full-length SA01-OmpA, including non-cytotoxicity, enhanced emulsifying capacity, and higher production yield. This study builds upon prior research by investigating the emulsifying properties of NT-OmpA under various environmental conditions, such as temperature, salinity, and pH. Molecular dynamics simulations and circular dichroism (CD) spectroscopy revealed significant alterations in the secondary structure of NT-OmpA under extreme conditions, specifically at alkaline pH (pH 11) and elevated temperatures (90 °C). CD spectroscopy showed a significant decrease in alpha-helical content and increased beta-sheet structures, validating NT-OmpA's pH stability. The NT-OmpA's effectiveness is investigated when combined with various polysaccharides to enhance its functional properties. Dextran (emulsification index of 76.94 ± 0.05%) exhibited superior emulsifying activity compared to glucose, agarose, starch, and NT-OmpA alone. NT-OmpA's emulsifying characteristics are considerably improved by dextran, making this combination a promising next-generation emulsifier. These findings underscore the structural resilience and functional adaptability of NT-OmpA, especially in challenging environmental conditions, and highlight its potential in industrial applications requiring robust emulsifying agents.