Enhancing biological hydrogen production from cyanobacteria by removal of excreted products
| Autor: | Nicholas J. Skizim, Gennady Ananyev, G. Charles Dismukes |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
Cyanobacteria
Hydrogen Photosystem II Cell Survival Carboxylic Acids chemistry.chemical_element Bioengineering Applied Microbiology and Biotechnology Milking chemistry.chemical_compound Bioreactors Hydrogenase Spirulina Biomass Photosynthesis Ethanol biology Glycogen food and beverages Electrochemical Techniques General Medicine Hydrogen-Ion Concentration NAD biology.organism_classification Dilution chemistry Biochemistry Biofuels Fermentation Arthrospira Metabolic Networks and Pathways NADP Biotechnology Nuclear chemistry |
| Zdroj: | Journal of Biotechnology. 162:97-104 |
| ISSN: | 0168-1656 |
| Popis: | Hydrogen is produced by a [NiFe]-hydrogenase in the cyanobacterium Arthrospira (Spirulina) maxima during autofermentation of photosynthetically accumulated glycogen under dark anaerobic conditions. Herein we show that elimination of H 2 backpressure by continuous H 2 removal (“milking”) can significantly increase the yield of H 2 in this strain. We show that “milking” by continuous selective consumption of H 2 using an electrochemical cell produces the maximum increase in H 2 yield (11-fold) and H 2 rate (3.4-fold), which is considerably larger than through “milking” by non-selective dilution of the biomass in media (increases H 2 yield 3.7-fold and rate 3.1-fold). Exhaustive autofermentation under electrochemical milking conditions consumes >98% of glycogen and 27.6% of biomass over 7–8 days and extracts 39% of the energy content in glycogen as H 2 . Non-selective dilution stimulates H 2 production by shifting intracellular equilibria competing for NADH from excreted products and terminal electron sinks into H 2 production. Adding a mixture of the carbon fermentative products shifts the equilibria towards reactants, resulting in increased intracellular NADH and an increased H 2 yield (1.4-fold). H 2 production is sustained for a period of time up to 7 days, after which the PSII activity of the cells decreases by 80–90%, but can be restored by regeneration under photoautotrophic growth. |
| Databáze: | OpenAIRE |
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