Enhancing photo‐catalytic production of organic acids in the cyanobacterium S ynechocystis sp. PCC 6803 Δ glg C , a strain incapable of glycogen storage
- Biosciences Center National Renewable Energy Laboratory 15013 Denver West Parkway Golden CO 80401 USA
We describe how a key objective in microbial biofuels strain development is to maximize carbon flux to target products while minimizing cell biomass accumulation, such that ideally the algae and bacteria would operate in a photo-catalytic state. A brief period of such a physiological state has recently been demonstrated in the cyanobacterium Synechocystis sp. PCC 6803 ΔglgC strain incapable of glycogen storage. When deprived of nitrogen, the ΔglgC excretes the organic acids alpha-ketoglutarate and pyruvate for a number of days without increasing cell biomass. This study examines the relationship between the growth state and the photo-catalytic state, and characterizes the metabolic adaptability of the photo-catalytic state to increasing light intensity. It is found that the culture can transition naturally from the growth state into the photo-catalytic state when provided with limited nitrogen supply during the growth phase. Photosynthetic capacity and pigments are lost over time in the photo-catalytic state. Reversal to growth state is observed with re-addition of nitrogen nutrient, accompanied by restoration of photosynthetic capacity and pigment levels in the cells. While the overall productivity increased under high light conditions, the ratio of alpha-ketoglutarate/pyruvate is altered, suggesting that carbon partition between the two products is adaptable to environmental conditions.
- Research Organization:
- National Renewable Energy Laboratory (NREL), Golden, CO (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Sustainable Transportation Office. Hydrogen Fuel Cell Technologies Office (HFTO)
- Grant/Contract Number:
- AC36-08GO28308
- OSTI ID:
- 1345698
- Alternate ID(s):
- OSTI ID: 1220612; OSTI ID: 1345699
- Report Number(s):
- NREL/JA-2700-62489
- Journal Information:
- Microbial Biotechnology (Online), Journal Name: Microbial Biotechnology (Online) Vol. 8 Journal Issue: 2; ISSN 1751-7915
- Publisher:
- Wiley-BlackwellCopyright Statement
- Country of Publication:
- United Kingdom
- Language:
- English
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