TY - JOUR
T1 - Altered carbohydrate metabolism in glycogen synthase mutants of Synechococcus sp. strain PCC 7002
T2 - Cell factories for soluble sugars
AU - Xu, Yu
AU - Tiago Guerra, L.
AU - Li, Zhongkui
AU - Ludwig, Marcus
AU - Charles Dismukes, G.
AU - Bryant, Donald A.
N1 - Funding Information:
This work was supported by the Air Force Office of Scientific Research (MURI grant FA9550-05-1-0365 ) which is gratefully acknowledged. LTG was supported by a doctoral fellowship FCT-MCTES (reference code SFRH/BD/61387/2009). The authors also acknowledge Dr. Martin Hagemann for generously providing the GG standard.
Copyright:
Copyright 2013 Elsevier B.V., All rights reserved.
PY - 2013/3
Y1 - 2013/3
N2 - Glycogen and compatible solutes are the major polymeric and soluble carbohydrates in cyanobacteria and function as energy reserves and osmoprotectants, respectively. Glycogen synthase null mutants (glgA-I glgA-II) were constructed in the cyanobacterium Synechococcus sp. strain PCC 7002. Under standard conditions the double mutant produced no glycogen and more soluble sugars. When grown under hypersaline conditions, the glgA-I glgA-II mutant accumulated 1.8-fold more soluble sugars (sucrose and glucosylglycer-(ol/ate)) than WT, and these cells spontaneously excreted soluble sugars into the medium at high levels without the need for additional transporters. An average of 27% more soluble sugars was released from the glgA-I glgA-II mutant than WT by hypo-osmotic shock. Extracellular vesicles budding from the outer membrane were observed by transmission electron microscopy in glgA-I glgA-II cells grown under hypersaline conditions. The glgA-I glgA-II mutant serves as a starting point for developing cell factories for photosynthetic production and excretion of sugars.
AB - Glycogen and compatible solutes are the major polymeric and soluble carbohydrates in cyanobacteria and function as energy reserves and osmoprotectants, respectively. Glycogen synthase null mutants (glgA-I glgA-II) were constructed in the cyanobacterium Synechococcus sp. strain PCC 7002. Under standard conditions the double mutant produced no glycogen and more soluble sugars. When grown under hypersaline conditions, the glgA-I glgA-II mutant accumulated 1.8-fold more soluble sugars (sucrose and glucosylglycer-(ol/ate)) than WT, and these cells spontaneously excreted soluble sugars into the medium at high levels without the need for additional transporters. An average of 27% more soluble sugars was released from the glgA-I glgA-II mutant than WT by hypo-osmotic shock. Extracellular vesicles budding from the outer membrane were observed by transmission electron microscopy in glgA-I glgA-II cells grown under hypersaline conditions. The glgA-I glgA-II mutant serves as a starting point for developing cell factories for photosynthetic production and excretion of sugars.
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U2 - 10.1016/j.ymben.2012.12.002
DO - 10.1016/j.ymben.2012.12.002
M3 - Article
C2 - 23262095
AN - SCOPUS:84872420422
VL - 16
SP - 56
EP - 67
JO - Metabolic Engineering
JF - Metabolic Engineering
SN - 1096-7176
IS - 1
ER -