Light dilution via wavelength management for efficient high-density photobioreactors.
The spectral distribution of light influences microalgae productivity; however, development of photobioreactors has proceeded largely without regard to spectral optimization. Here, we use monochromatic light to quantify the joint influence of path length, culture density, light intensity, and wavelength on productivity and efficiency in Synechococcus elongatus. The productivity of green light was ∼4× that of red at the highest levels of culture density, depth, and light intensity. This performance is attributed to the combination of increased dilution and penetration of this weakly absorbed wavelength over a larger volume fraction of the reactor. In contrast, red light outperformed other wavelengths in low-density cultures with low light intensities. Low-density cultures also adapted more rapidly to reduce absorption of longer wavelengths, allowing for prolonged cultivation. Taken together, these results indicate that, particularly for artificially lit photobioreactors, wavelength needs to be included as a critical operational parameter to maintain optimal performance. Biotechnol. Bioeng. 2017;114: 1160-1169. © 2017 Wiley Periodicals, Inc.
Department of Mechanical and Industrial Engineering, Institute for Sustainable Energy, University of Toronto, 5 King's College Road, Toronto, M5S 3G8,, Ontario, Canada.
Matthew D
MD
Ooms
Department of Mechanical and Industrial Engineering, Institute for Sustainable Energy, University of Toronto, 5 King's College Road, Toronto, M5S 3G8,, Ontario, Canada.
Percival J
PJ
Graham
Department of Mechanical and Industrial Engineering, Institute for Sustainable Energy, University of Toronto, 5 King's College Road, Toronto, M5S 3G8,, Ontario, Canada.
Brian
http://orcid.org/0000-0001-9425-1932
B
Nguyen
Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada.
Edward H
EH
Sargent
Department of Mechanical and Industrial Engineering, Institute for Sustainable Energy, University of Toronto, 5 King's College Road, Toronto, M5S 3G8,, Ontario, Canada.
David
D
Sinton
D049109:Cell Proliferation / Q000502:physiology / Q000528:radiation effects; D003116:Color; D004307:Dose-Response Relationship, Radiation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007909:Lenses; D008029:Lighting / Q000295:instrumentation* / Q000379:methods; D010775:Photic Stimulation / Q000295:instrumentation* / Q000379:methods; D058433:Photobioreactors / Q000382:microbiology*; D010788:Photosynthesis / Q000502:physiology* / Q000528:radiation effects; D011829:Radiation Dosage; D012031:Refractometry / Q000295:instrumentation / Q000379:methods; D046940:Synechococcus / Q000502:physiology* / Q000528:radiation effects*
cyanobacteria; light dilution; microalgae; photobioreactor; productivity