title: Development of a cell immobilization technique for the conversion of polysialogangliosides to monosialotetrahexosylganglioside.
abstract: BACKGROUND
  Monosialotetrahexosylganglioside (GM₁) prepared from the brain of pig or bovine is an effective clinical drug in the treatment of different nervous system diseases. Generally, polysialogangliosides are transformed into GM₁ by enzymic or chemical hydrolysis due to the very poor level of natural GM₁.
  
  
  OBJECTIVE
  To continuously obtain GM₁ by cell immobilization in a packed-bed reactor.
  
  
  METHODS
  Brevibacterium casei, which is Gram-positive bacteria belonging to the order Actinomyces and family Brevibacteriaceae, can produce high-activity sialidase, are encapsulated in silk fibroin hydrogel, and subsequently packed into a reactor. The crude ganglioside is pumped into the reactor and continuously turned to GM₁.
  
  
  RESULTS
  The optimal silk fibroin concentration for hydrogel preparation is 6.0% (w/v). The optimal initial biomass for immobilization is ~12% (wet weight). The optimal conversion conditions are 35 °C and 6  mL/min of flow rate. Under above conditions, the maximum GM₁ productive strength and conversion ratio can reach to 4.2 g/L·h and 313.5%, respectively.
  
  
  CONCLUSIONS
  Silk fibroin is a promising material for cell immobilization because it has predominant characteristics of higher permeability and intensity. Cell immobilization for continuous GM₁ transformation could eliminate the asialo GM₁ and decrease the foreign matter from transfer medium and metabolism product.
  
  
  CONCLUSIONS
  In the packed-bed reactor, continuous production of GM₁ had been under effective running at least for 15 days indicating a potential for industrial production. It is significant that this is a first report on cell immobilization for GM₁ production.
authors.affiliation: Research and Design Center, Lunan Pharmaceutical Group Corporation, Linyi, China. donghuijun_747@163.com
authors.forename: H J
authors.initials: HJ
authors.lastname: Dong
authors.forename: J Y
authors.initials: JY
authors.lastname: Jiang
authors.forename: Q L
authors.initials: QL
authors.lastname: Chen
mesh_terms: D000818:Animals; D001431:Bacteriological Techniques / Q000379:methods*; D019149:Bioreactors / Q000382:microbiology; D012831:Bombyx / Q000378:metabolism; D001951:Brevibacterium / Q000378:metabolism; D018914:Cells, Immobilized / Q000378:metabolism; D005732:Gangliosides / Q000032:analysis / Q000378:metabolism / Q000502:physiology*; D020100:Hydrogels / Q000378:metabolism; D008962:Models, Theoretical; D009439:Neuraminidase / Q000032:analysis; D013552:Swine
chemical_list: D005732:Gangliosides; D020100:Hydrogels; C025447:sialogangliosides; C016481:trisialoganglioside GT1; D009439:Neuraminidase