Mechanism analysis of effect of oxygen on molecular weight of hyaluronic acid produced by Streptococcus zooepidemicus.
Dissolved oxygen (DO) has a significant effect on the molecular weight of hyaluronic acid (HA) during the fermentation of Streptococcus zooepidemicus. Therefore, to further investigate the effect of DO on the yield and molecular weight of HA, this study compared the metabolic flux distribution of S. zooepidemicus under aerobic conditions at various DO levels. The metabolic flux analysis demonstrated that the HA synthesis pathway, considered a dependent network, was little affected by the DO level. In contrast, the fluxes of lactate and acetate were greatly influenced, and more ATP was generated concomitant with acetate at a high DO level. Furthermore, the has gene expression and HA synthase activity were both repressed under anaerobic conditions, yet not obviously affected under aerobic conditions at various DO levels. Therefore, it was concluded that the HA molecular weight would seem to depend on the concomitant effect of the generation of ATP and reactive oxygen species. It is expected that this work will contribute to a better understanding of the effect of the DO level on the mechanism of the elongation of HA chains.
Duan
Xu-Jie
XJ
State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, P.R.China.
Niu
Hong-Xing
HX
Tan
Wen-Song
WS
Zhang
Xu
X
D000085:Acetates / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D005285:Fermentation; D015964:Gene Expression Regulation, Bacterial; D014453:Glucuronosyltransferase / Q000096:biosynthesis / Q000235:genetics; D000076002:Hyaluronan Synthases; D006820:Hyaluronic Acid / Q000737:chemistry / Q000378:metabolism; D007700:Kinetics; D019344:Lactic Acid / Q000378:metabolism; D053858:Metabolic Networks and Pathways; D008970:Molecular Weight; D010100:Oxygen / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D018502:Streptococcus equi / Q000235:genetics / Q000378:metabolism*
D000085:Acetates; D017382:Reactive Oxygen Species; D019344:Lactic Acid; D000255:Adenosine Triphosphate; D006820:Hyaluronic Acid; D014453:Glucuronosyltransferase; D000076002:Hyaluronan Synthases; D010100:Oxygen