Characterization of CCK-oligosaccharides from Leu. lactis

The CCK-oligosaccharides produced by Leu. lactis CCK940 were analyzed using a HPAEC-PAD (DX 500 Chromatography System, Dionex, Sunnyvale, CA, USA) [14 (link)]). The Leu. lactis CCK940 culture was centrifuged at 27,237× g for 1 min and the supernatant was analyzed by HPAEC-PAD (Dionex) with a CarboPac PA-1 column (4 × 250 mm, Dionex) and a CarboPac PA-1 guard column (4 × 50 mm, Dionex). The flow rate was 1.0 mL/min, and the mobile phase used for oligosaccharide separation was 150 mM sodium hydroxide for the first 20 min; subsequently, 600 mM sodium acetate (in 150 mM sodium hydroxide) was applied with a gradient of 60:40 to 0:100 from 20 to 25 min, and 150 mM sodium hydroxide was used from 25 to 40 min (sodium hydroxide, Fisher Scientific, Hampton, NH, USA; sodium acetate, Sigma-Aldrich). Ten microliters of each sample was injected for each analysis.