Evaluation of experimental conditions that influence hydrogen production among heterocystous Cyanobacteria
✍ Scribed by Chris M. Yeager; Charles E. Milliken; Christopher E. Bagwell; Lauren Staples; Polly A. Berseth; Henry T. Sessions
- Publisher
- Elsevier Science
- Year
- 2011
- Tongue
- English
- Weight
- 856 KB
- Volume
- 36
- Category
- Article
- ISSN
- 0360-3199
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✦ Synopsis
The overall goal of this research was to systematically evaluate H 2 production among different heterocystous cyanobacteria in response to defined experimental variables including N 2 and O 2 concentration, carbon source, and light intensity. N 2 elicited an immediate reduction of H 2 production rates and the magnitude of the effect was strikingly similar across the diverse collection of heterocystous cyanobacteria that were tested. At the N 2 :O 2 ratio found in air (4:1), N 2 was a much more potent inhibitor of H 2 production than O 2 . Low levels of O 2 (1e5% headspace, vol:vol) were generally found to support optimal H 2 production. Glucose addition (10 mM) stimulated light-dependent H 2 production in 8 of 10 cyanobacteria examined, eliciting a 2e11 fold increase in production rates and 2e45 fold increase in yields. The addition of glucose also effectively lowered the intensity of light required for optimal H 2 production in 4 of 10 strains tested. H 2 production rates ranged from 1 to 50 mmol mg chl a À1 h À1 . The results from this study provide important benchmark phenotypes against which to evaluate newly discovered H 2producing heterocystous cyanobacteria, and we discuss how these findings highlight the necessity of a multi-parameter approach to comprehensively screen for superior H 2producing heterocystous cyanobacteria.