Synechococcus elongatus PCC

It has been shown that the enantioselectivity of the reduction of ketones by the photosynthetic cyanobacterium Synechococcus elongatus PCC 7942 is regulated by light. In the case of the ketone (28), the enantioselectivity is reduced by over 50% in the absence of light (Nakamura and Yamanaka, Chapter 5). It was also shown that a known photosynthesis inhibitor decreases both the chemical and enantiomeric purities of the products, which suggests that physiological changes on irradiation alfect the enzymatic activity of cyanobacteria. 

Isobutanol production as an alternative metabolic sink to rescue the growth deficiency of the glycogen mutant of Synechococcus elongatus PCC 7942. Photosynth. Res., 120, 301-310. 

Two cyanobacteria also contain these enzymes (Table 106.3). Synechococcus elongatus PCC 7942 contains a functional CrtL [38]. Prochlorococcus marinus MED4 contains two lycopene cyclases, CrtL-b and CrtL-e. CrtL-b exhibits lycopene p-cyclase activity, whereas CrtL-e is a bifunctional enzyme having both lycopene s-cyclase and lycopene (3-cyclase activities [39]. The combination of these two cyclases allows the production of (3-carotene, a-carotene, and E-carotene. Both enzymes might have originated from the dupUcation of a single gene. The characteristics of this CrtL-e are somewhat different from those observed in land plants [40]. 

Cell of Synechococcus elongatus PCC 7942 Figure 10.12 Reduction of ketone with photosynthetic biocatalyst using light energy. ... 

Introduction of foreign DNA into cyanobacteria has been demonstrated in laboratory for several strains, and is now a common practice [50]. A few unicellular cyanobacteria are naturally competent for transformation, and can uptake foreign DNA from their environment in the form of plasmid or linear DNA [51]. Among naturally competent strains are the model freshwater cyanobacteria S. elongatus PCC 7942 and Synechocystis PCC 6803, as well as the marine Synechococcus PCC 7002 and the thermophile Jhermosynechococcus elongatus BP-1 [52—56]. 

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