Response of H2 production and Hox-hydrogenase activity to external factors in the unicellular cyanobacterium Synechocystis sp. strain PCC 6803
✍ Scribed by Wipawee Baebprasert; Peter Lindblad; Aran Incharoensakdi
- Publisher
- Elsevier Science
- Year
- 2010
- Tongue
- English
- Weight
- 254 KB
- Volume
- 35
- Category
- Article
- ISSN
- 0360-3199
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✦ Synopsis
The effects of external factors on both H 2 production and bidirectional Hox-hydrogenase activity were examined in the non-N 2 -fixing cyanobacterium Synechocystis PCC 6803.
Exogenous glucose and increased osmolality both enhanced H 2 production with optimal production observed at 0.4% and 20 mosmol kg À1 , respectively. Anaerobic condition for 24 h induced significant higher H 2 ase activity with cells in BG11 0 showing highest activities.
Increasing the pH resulted in an increased Hox-hydrogenase activity with an optimum at pH 7.5. The Hox-hydrogenase activity gradually increased with increasing temperature from 30 B C to 60 B C with the highest activity observed at 70 B C. A low concentration at 100 mM of either DTT or b-mercaptoethanol resulted in a minor stimulation of H 2 production. b-Mercaptoethanol added to nitrogen-and sulfur-deprived cells stimulated H 2 production significantly. The highest Hox-hydrogenase activity was observed in cells in BG11 0 -S-deprived condition and 750 mM b-mercaptoethanol measured at a temperature of 70 C; 14.32 mmol H 2 mg chl a À1 min À1 .