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Electron partitioning in soluble organic products by wild-type and modified Synechocystis sp. PCC 6803
- Nguyen, Binh T., Rittmann, Bruce E.
- Biomass and bioenergy 2016 v.90 pp. 237-242
- Synechocystis, biomass, carbon, chemical oxygen demand, dodecanoic acid, electrons, embodied energy, light intensity, photosynthesis
- The partitioning of electrons photosynthetically fixed in carbon by the cyanobacterium Synechocystis sp. PCC 6803 was evaluated for up to 24-day batch cultures continuously exposed to incident light intensity (LI) from 111 to 598 μEm−2 s−1. The fate of fixed electrons was assayed by Chemical Oxygen Demand (COD) in biomass, generic soluble microbial products (SMP), and excreted laurate (for a modified strain). Because SMP is not a valuable product, light energy embedded in SMP is wasted. Normalized to the total COD (TCOD), wild-type Synechocystis partitioned 75–84% of its TCOD in particulate biomass and 16–25% in generic SMP. A strain modified to excrete lauric acid partitioned 6.6%–10% of its TCOD in laurate, 21%–30% in generic SMP, and 64%–69% in particulate biomass. The greatest electron partitioning in SMP occurred with the highest LI tested, which suggests that moderating the LI in the photobioreactor is a promising mean to accentuate the production of valuable forms of photosynthetically fixed electrons.