US 12,122,855 B2
Method for extracting pullulan polysaccharide from high-viscosity fermentation broth
Changsheng Qiao, Tianjin (CN); Ganggang Cheng, Tianjin (CN); Liang Lu, Tianjin (CN); Tingbin Zhao, Tianjin (CN); and Zhenhai Li, Tianjin (CN)
Assigned to TIANJIN UNIVERSITY OF SCIENCE AND TECHNOLOGY, Tianjin (CN)
Filed by TIANJIN UNIVERSITY OF SCIENCE AND TECHNOLOGY, Tianjin (CN)
Filed on Apr. 5, 2024, as Appl. No. 18/627,748.
Application 18/627,748 is a continuation of application No. PCT/CN2022/114968, filed on Aug. 26, 2022.
Claims priority of application No. 202111180191.0 (CN), filed on Oct. 11, 2021.
Prior Publication US 2024/0247082 A1, Jul. 25, 2024
Int. Cl. C08B 37/00 (2006.01)
CPC C08B 37/0003 (2013.01) [C08B 37/0018 (2013.01)] 11 Claims
 
1. A method for extracting pullulan polysaccharide from a fermentation broth having a viscosity of 200-350 mPa·s, wherein the method comprises following steps:
(1) removal of cells from the fermentation broth, comprising: adjusting the fermentation broth to a pH of 3-5 with HCl solution, adding chitosan dissolved in glacial acetic acid, heating to a temperature of 30-50° C., leaving to stand for 10-30 mins at the temperature of 30-50° C. for flocculating, and centrifuging to remove the cells and insoluble substance, so as to obtain a cell-free fermentation broth;
(2) removal of proteins, comprising: adjusting the cell-free fermentation broth to a pH of 8-9 with NaOH solution, leaving to stand for 15-30 mins for precipitating, centrifuging, then adding alkaline protease in supernatant, heating to a temperature of 40-50° C. for 2-3 hrs, deactivating the protease, and centrifuging to remove the proteins;
(3) decolorization, comprising: adjusting a resultant fermentation broth from step (2) to a pH of 3-5 with HCl solution, adding macroporousresin therein, heating to 30° C. for 1.5 hrs under stirring, so as to remove pigments, and then filtering to recycle the macroporous resin;
(4) removal of ions by an ultrafiltration membrane module, comprising: subjecting a resultant fermentation broth from step (3) to ultrafiltration for desalination through the ultrafiltration membrane module, and repeatedly the ultrafiltration until pullulan polysaccharide reaches a concentration of 5-8 g/100 mL; and
(5) drying, crushing and packaging.