Combinatorial deletions of glgC and phaCE enhance ethanol production in Synechocystis sp. PCC 6803.
Synechocystis sp. PCC 6803 is an attractive host for bio-ethanol production. In the present study, a nitrogen starvation approach was applied on an ethanol producing strain for inhibiting the growth, since ethanol production competes with the cell growth. The effect of gene deletions in the glycogen and polyhydroxybutyrate (PHB) synthesis pathways was investigated. Measurements of intracellular glycogen and PHB revealed that the glycogen was accumulated under the nitrogen starvation condition and the gene deletion of glycogen synthesis pathway caused the accumulation of PHB. The ethanol producing strain harboring deletions for both the glycogen and the PHB synthesis pathways (ΔglgCΔphaCE/EtOH) produced ethanol at the specific rate of 240mgg (dry cell weight)-1day-1under the nitrogen starvation condition. In a high cell density culture (OD730=50) using this ΔglgCΔphaCE/EtOH strain, the ethanol production rates were 1.08 and 2.01gL-1day-1under light conditions of 40 and 80μmolm-2s-1, respectively.
Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, 1-5 Yamadaoka, Suita, Osaka 565-0871, Japan.
Katsunori
K
Namakoshi
Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, 1-5 Yamadaoka, Suita, Osaka 565-0871, Japan.
Tubasa
T
Nakajima
Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, 1-5 Yamadaoka, Suita, Osaka 565-0871, Japan.
Katsunori
K
Yoshikawa
Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, 1-5 Yamadaoka, Suita, Osaka 565-0871, Japan.
Yoshihiro
Y
Toya
Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, 1-5 Yamadaoka, Suita, Osaka 565-0871, Japan. Electronic address: shimizu@ist.osaka-u.ac.jp.
Hiroshi
H
Shimizu
D000431:Ethanol / Q000032:analysis / Q000378:metabolism*; D017353:Gene Deletion; D005798:Genes, Bacterial / Q000235:genetics*; D005818:Genetic Engineering / Q000379:methods*; D006003:Glycogen / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D046939:Synechocystis / Q000235:genetics* / Q000378:metabolism*
D000431:Ethanol; D006003:Glycogen; D009584:Nitrogen
Ethanol production; Glycogen; Nitrogen starvation; Polyhydroxybutyrate; Synechocystis sp. PCC 6803