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Title: Enhancing photo‐catalytic production of organic acids in the cyanobacterium S ynechocystis sp.   PCC 6803 Δ glg C , a strain incapable of glycogen storage

Journal Article · · Microbial Biotechnology (Online)
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  1. Biosciences Center National Renewable Energy Laboratory 15013 Denver West Parkway Golden CO 80401 USA
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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
Citation Metrics:
Cited by: 14 works
Citation information provided by
Web of Science

References (10)

Impaired glycogen synthesis causes metabolic overflow reactions and affects stress responses in the cyanobacterium Synechocystis sp. PCC 6803 journal October 2012
Engineering Limonene and Bisabolene Production in Wild Type and a Glycogen-Deficient Mutant of Synechococcus sp. PCC 7002 journal June 2014
Isobutanol production as an alternative metabolic sink to rescue the growth deficiency of the glycogen mutant of Synechococcus elongatus PCC 7942 journal March 2014
Rhythms in Energy Storage Control the Ability of the Cyanobacterial Circadian Clock to Reset journal August 2014
Glycogen synthesis is a required component of the nitrogen stress response in Synechococcus elongatus PCC 7942 journal March 2013
Aquatic phototrophs: efficient alternatives to land-based crops for biofuels journal June 2008
Engineering cyanobacteria for the production of a cyclic hydrocarbon fuel from CO 2 and H 2 O journal January 2014
Photosynthesis-to-fuels: from sunlight to hydrogen, isoprene, and botryococcene production journal January 2012
Time-series resolution of gradual nitrogen starvation and its impact on photosynthesis in the cyanobacterium Synechocystis PCC 6803 journal March 2012
Nitrogen Starvation-Induced Chlorosis in Synechococcus PCC 7942. Low-Level Photosynthesis As a Mechanism of Long-Term Survival journal May 2001

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Related Subjects

09 BIOMASS FUELS
Synechocystis sp.
photo-catalysis
organic acids