1. State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, Qingdao 266237, Shandong, P. R. China
2. School of Chemistry and Environment, Jiaying University, Meizhou 514015, Guangdong, P. R. China
3. Laboratory of Marine Drugs and Biological Products, Pilot National Laboratory for Marine Science and Technology, 168 Weihai Road, Qingdao 266237, Shandong, P. R. China