1. Taishan College, Shandong University, 266237 Qingdao, China
2. COFCO Nutrition and Health Research Institute, 102209 Beijing, China
3. National Glycoengineering Research Center, Shandong University, 266237 Qingdao, China
4. State Key Laboratory of Microbial Technology, Shandong University, 266237 Qingdao, China