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 · Thu Jan 22 23:00:00 EST 2015 · Microbial Biotechnology (Online)

DOI: https://doi.org/10.1111/1751-7915.12243 · OSTI ID:1345698

Carrieri, Damian ^[1]; Broadbent, Charlie ^[1]; Carruth, David ^[1]; Paddock, Troy ^[1]; Ungerer, Justin ^[1]; Maness, Pin‐Ching ^[1]; Ghirardi, Maria ^[1]; Yu, Jianping ^[1]

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1. Biosciences Center National Renewable Energy Laboratory 15013 Denver West Parkway Golden CO 80401 USA

Summary 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 S ynechocystis sp.   PCC 6803 Δ glgC strain incapable of glycogen storage. When deprived of nitrogen, the Δ glgC 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.

• Sponsoring Organization: USDOE
• OSTI ID: 1345698
• Journal Information: Microbial Biotechnology (Online), Journal Name: Microbial Biotechnology (Online) Journal Issue: 2 Vol. 8; ISSN 1751-7915
• Publisher: Wiley-BlackwellCopyright Statement
• Country of Publication: United Kingdom
• Language: English