초록 |
An experimental study was carried out on the production of β-glucans, a group of immuno-stimulating exopolysaccharides, by Agaricus blazei in submerged batch cultures. Effects of dissolved oxygen concentration (DOC) on cell growth and exopolysaccharides production were investigated in a 7L bioreactor system. DOC showed no significant effects over 20 % of air saturation. When DOC was controlled at about 20 % by manipulation of agitation speed, cellular and exopolysaccharides productivities were observed to increase by 41 % and 100 %, respectively, as compared to the control (cultures with no DOC control). The cellular and exopolysaccharides productivities at 20% of DOC were 0.131 g/L-h and 0.097 g/L-h, respectively. When DOC was controlled at about 20 % by manipulating pure oxygen supply at a fixed agitation speed, cellular and exopolysaccharides productivities were observed to be 42 % and 70 % higher, respectively, than the control. These results implied that an increased shear stress caused by more rigorous agitation speed as in the first case without pure oxygen supply might have had a positive effect on exopolysaccharides production. |