Preparation of lactosucrose catalyzed by levansucrase and evaluation of its prebiotic activity

Prebiotics play an important role in biological processes, which has stimulated great interest in their synthesis. This paper reports a levansucrase from Bacillus subtilis, demonstrating high catalytic selectivity for the synthesis of prebiotic lactosucrose with sucrose as a donor and lactose as an acceptor. The product was purified and the structure was characterized. The effects of lactosucrose on the proliferation and acid production of bifidobacterium and lactobacillus were better than that of lactulose and galactooligosaccharides(GOS). The short chain fatty acid (SCFA) content in the fermentation broth was also measured. It contains large amounts of SCFAs that act roles in intestinal homeostasis. The lactosucrose affected inflammatory responses in lipopolysaccharide-induced RAW 264.7 macrophages since they suppressed inflammatory cytokines TNF-alpha, IL-1 beta, and IL-6 well as compared to the control. Also, lactosucrose had no cytotoxicity in the concentration range of 10 mg/mL. These results indicate that lactosucrose was effective in promoting the proliferation of intestinal probiotics and have anti-inflammatory activity. Therefore, lactosucrose has positive prebiotic activity.