mheslep
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I was referring to a general photosynthetic limit of about 11% for any from sources like this:Ivan Seeking said:Algae is nowhere near the photosynthetic limit. Just check the PAR for any strain and that is easy to see. I want to say that most high-yield strains are in the 20% range, but I don't recall the reference for that. It also depends on what we mean by the limit. For example, UV is not used for hydrocarbon production and can damage the cell. All PAR charts that I saw ended at UV frequencies.
http://www.fao.org/docrep/w7241e/w7241e05.htm#1.2.1 photosynthetic efficiencyRenewable biological systems for alternative sustainable energy production said:[...]Only light within the wavelength range of 400 to 700 nm (photosynthetically active radiation, PAR) can be utilized by plants, effectively allowing only 45 % of total solar energy to be utilized for photosynthesis. Furthermore, fixation of one CO2 molecule during photosynthesis, necessitates a quantum requirement of ten (or more), which results in a maximum utilization of only 25% of the PAR absorbed by the photosynthetic system. On the basis of these limitations, the theoretical maximum efficiency of solar energy conversion is approximately 11%.
I see references on various algae strains at http://www.bioenergywiki.net/images/d/de/Egger_Energy_Efficiency.pdf" (page 9). Thus this bio-isobutanol process, if it is indeed 50% higher yield than algae, would be at or near the photosynthetic limit.
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