Construction of a cyanobacterium synthesizing cyclopropane fatty acids.
Microalgae have received much attention as a next-generation source of biomass energy. However, most of the fatty acids (FAs) from microalgae are multiply unsaturated; thus, the biofuels derived from them are fluid, but vulnerable to oxidation. In this study, we attempted to synthesize cyclopropane FAs in the cyanobacterium Synechocystis sp. PCC 6803 by expressing the cfa gene for cyclopropane FA synthase from Escherichia coli with the aim of producing FAs that are fluid and stable in response to oxidization. We successfully synthesized cyclopropane FAs in Synechocystis with a yield of ~30% of total FAs. Growth of the transformants was altered, particularly at low temperatures, but photosynthesis and respiration were not significantly affected. C16:1(∆9) synthesis in the desA(-)/desD(-) strain by expression of the desC2 gene for sn-2 specific ∆9 desaturase positively affected growth at low temperatures via promotion of various cellular processes, with the exceptions of photosynthesis and respiration. Estimation of the apparent activities of desaturases suggested that some acyl-lipid desaturases might recognize the lipid side chain.
Graduate School of Life and Environmental Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8572, Japan.
Shuntaro
S
Machida
Faculty of Life and Environmental Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8572, Japan; Japan Science and Technology Agency, CREST.
Yoshihiro
Y
Shiraiwa
Faculty of Life and Environmental Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8572, Japan. Electronic address: iwanes6803@biol.tsukuba.ac.jp.
Iwane
I
Suzuki
D000595:Amino Acid Sequence; D018533:Biomass; D000458:Cyanobacteria / Q000235:genetics / Q000378:metabolism*; D003521:Cyclopropanes; D004926:Escherichia coli / Q000235:genetics; D044943:Fatty Acid Desaturases / Q000737:chemistry / Q000235:genetics*; D005227:Fatty Acids / Q000096:biosynthesis* / Q000235:genetics; D008055:Lipids; D010788:Photosynthesis / Q000235:genetics; D046939:Synechocystis / Q000235:genetics / Q000378:metabolism
D003521:Cyclopropanes; D005227:Fatty Acids; D008055:Lipids; C028775:cyclopropane fatty acids; D044943:Fatty Acid Desaturases
Acyl-lipid desaturase; Biofuel; Cyclopropane fatty acid; Microalgae; Synechocystis sp. PCC 6803