Effect of oxygen and shear stress on molecular weight of hyaluronic acid.
Dissolved oxygen (DO) and shear stress have pronounced effects on hyaluronic acid (HA) production, yet various views persist about their effect on the molecular weight of HA. Accordingly, this study investigated the effects of DO and shear stress during HA fermentation. The results showed that both cell growth and HA synthesis were suppressed under anaerobic conditions, and the HA molecular mass was only (1.22+/-0.02) x 106 Da. Under aerobic conditions, although the DO level produced no change in the biomass or HA yield, a high DO level favored the HA molecular mass, which reached a maximum value of (2.19+/- 0.05) x 106 Da at 50% DO. Furthermore, a high shear stress delayed the rate of HA synthesis and decreased the HA molecular weight, yet had no clear effect on the HA yield. Therefore, a high DO concentration and mild shear environment would appear to be essential to enhance the HA molecular weight.
Duan
Xu-Jie
XJ
State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, P.R.China.
Yang
Li
L
Zhang
Xu
X
Tan
Wen-Song
WS
D018533:Biomass; D019149:Bioreactors; D005285:Fermentation; D006820:Hyaluronic Acid / Q000737:chemistry* / Q000378:metabolism*; D008970:Molecular Weight; D010100:Oxygen / Q000378:metabolism*; D033081:Shear Strength; D018502:Streptococcus equi / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D014783:Viscosity
D006820:Hyaluronic Acid; D010100:Oxygen