Enhanced hyaluronic acid production of Streptococcus zooepidemicus by an intermittent alkaline-stress strategy
Open Access
- 24 January 2008
- journal article
- research article
- Published by Oxford University Press (OUP) in Letters in Applied Microbiology
- Vol. 46 (3), 383-388
- https://doi.org/10.1111/j.1472-765x.2008.02325.x
Abstract
Aims: Enhanced hyaluronic acid (HA) production of Streptococcus zooepidemicus by redirecting carbon flux through an intermittent alkaline‐stress strategy. Methods and Results: pH value was kept at 7·0 for the first 6 h, and then intermittently switched to 8·5 for 1 h and back to 7·0 for 1 h until the end of fermentation at 16 h (one pH switch cycle every 2 h). With this intermittent alkaline‐stress strategy, HA production was increased to 6·5 ± 0·2 g l−1 from 5·0 ± 0·1 g l−1 of the control, in which pH was always kept at 7·0. In addition, biomass and lactic acid concentration decreased by 24% and 14%, respectively, while acetic acid concentration increased by 10% under intermittent alkaline stress. The redirection of carbon flux from lactic acid to acetic acid was further supported by the decreased lactate dehydrogenase activity and the increased acetate kinase activity. As indicated by the increased NADH oxidase (NOX) activity, intermittent alkaline‐stress induced a more oxidative intracellular environment which would facilitate HA synthesis. Conclusions: Overproduction of HA was realized by redirecting carbon flux through the proposed intermittent alkaline‐stress strategy. Significance and Impact of the Study: This study clearly demonstrated the importance of metabolic‐pathway‐analysis based fermentation strategy in industrial processes and provided an alternative optimization approach for high viscosity fermentation.Keywords
This publication has 16 references indexed in Scilit:
- The role of dissolved oxygen and function of agitation in hyaluronic acid fermentationBiochemical Engineering Journal, 2006
- Salt stress effects on the central and carnitine metabolisms ofEscherichia coliBiotechnology & Bioengineering, 2006
- Analysis of metabolic fluxes for hyaluronic acid (HA) production by Streptococcus zooepidemicusWorld Journal of Microbiology and Biotechnology, 2006
- Microbial hyaluronic acid productionApplied Microbiology and Biotechnology, 2004
- Hyaluronan-based microspheres as tools for drug delivery: a comparative studyInternational Journal of Pharmaceutics, 2004
- Aerobic cultivation of Streptococcus zooepidemicus and the role of NADH oxidaseBiochemical Engineering Journal, 2003
- Amplifying the cellular reduction potential of Streptococcus zooepidemicusJournal of Biotechnology, 2003
- Productivity of concentrated hyaluronic acid using a Maxblend® fermentorJournal of Bioscience and Bioengineering, 1999
- A Rapid and Sensitive Method for the Quantitation of Microgram Quantities of Protein Utilizing the Principle of Protein-Dye BindingAnalytical Biochemistry, 1976
- A modified uronic acid carbazole reactionAnalytical Biochemistry, 1962