BioChem - DOS

Enhancing photo-catalytic production of organic acids in the cyanobacterium Synechocystis sp. PCC 6803 ΔglgC, a strain incapable of glycogen storage

Microbial biotechnology

Carrieri, Damian; Broadbent, Charlie; Carruth, David; Paddock, Troy; Ungerer, Justin; Maness, Pin-Ching; Ghirardi, Maria; Yu, Jianping

<P>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 <I>S</I><I>ynechocystis sp.</I>&#x2005;PCC 6803 &Delta;<I>glgC</I> strain incapable of glycogen storage. When deprived of nitrogen, the &Delta;<I>glgC</I> 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.</P>

2015

BlackWell Publishing Ltd

1751-7907

1751-7915

8

2

pp.275-280

10.1111/1751-7915.12243

http://click.ndsl.kr/servlet/OpenAPIDetailView?keyValue=05787966&target=NART&cn=NART71613439