Development of a cell immobilization technique for the conversion of polysialogangliosides to monosialotetrahexosylganglioside

Objective: To continuously obtain GM(1) by cell immobilization in a packed-bed reactor. Materials and 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 GM(1). Results: The optimal silk fibroin concentration for hydrogel preparation is 6.0% (w/v). The optimal initial biomass for immobilization is similar to 12% (wet weight). The optimal conversion conditions are 35 degrees A degrees C and 6 mL/min of flow rate. Under above conditions, the maximum GM(1) productive strength and conversion ratio can reach to 4.2 g/L center dot center dot h and 313.5%, respectively. Discussion: Silk fibroin is a promising material for cell immobilization because it has predominant characteristics of higher permeability and intensity. Cell immobilization for continuous GM(1) transformation could eliminate the asialo GM(1) and decrease the foreign matter from transfer medium and metabolism product. Conclusion: In the packed-bed reactor, continuous production of GM(1) 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 GM(1) production.