Sucrose medium osmolality as a regulator of anabolic and catabolic parameters in Zymomonas culture
✍ Scribed by A. Vigants; P. Zikmanis; M. Bekers
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 334 KB
- Volume
- 16
- Category
- Article
- ISSN
- 0138-4988
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
This study focuses on the growth of Zymomonas mobilis strain 113 S and its ethanol and levan production under the conditions of increasing sucrose medium osmolality caused by NaCl, KCl, sorbitol or maltose. The increase in medium osmolality (700–1,500 mosml/kg) was accompanied by the inhibition of growth (growth rate, biomass yield) and ethanol production (specific productivity and yield) In contrast, levan synthesis was less affected or even stimulated and, as a consequence, levan specific productivity was increased significantly. A decrease in the anabolic growth parameters correlated with a parallel inhibition of glucose‐6‐P dehydrogenase and alcohol dehydrogenase (isoenzyme ADH II) activities. A significant inverse linear relationship (r = − 0.932, 1 − P = 0.01) was observed between the values of the specific productivities of ethanol and levan. This relationship was confirmed independently by a controlled reduction of growth and ethanol productivity (3.75–4.75 mM sodiumbisulphite as an acceptor of acetaldehyde formed in the pyruvate decarboxylase reaction). As further support of this relationship, a significant inverse correlation was observed between levan specific productivity and ATP concentration in Zymomonas mobilis cells, most probably demonstrating that a reduced level of energetic metabolism is favourable for levan production.