Elsevier

Algal Research

Volume 15, April 2016, Pages 32-42
Algal Research

Impact of light color on photobioreactor productivity

https://doi.org/10.1016/j.algal.2016.01.015Get rights and content
Under a Creative Commons license
open access

Highlights

  • Blue and red light are suboptimal for mass cultivation of microalgae.

  • Highest areal productivity was found for cultures grown under warm white and yellow light.

  • Blue light supplementation to yellow light increased growth and culture fitness.

  • Biomass specific light absorption is inversely correlated to productivity.

Abstract

Microalgae perform photosynthesis at a high efficiency under low light conditions. However, under bright sunlight, it is difficult to achieve a high photosynthetic efficiency, because cells absorb more light energy than can be converted to biochemical energy. Consequently microalgae dissipate part of the absorbed light energy as heat. The objective of this study was to investigate photobioreactor productivity as a function of the biomass specific light absorption rate. A strategy to circumvent oversaturation is to exploit light with a spectral composition that minimizes light absorption. We studied productivity of Chlamydomonas reinhardtii cultivated under different colors of light. The incident light intensity was 1500 μmol photons m 2 s 1, and cultivation took place in turbidostat controlled lab-scale panel photobioreactors. Our results demonstrate that, under mass culture conditions, productivity and biomass specific light absorption are inversely correlated. The highest productivity, measured under continuous illumination, was obtained using yellow light (54 g m 2 d 1) while blue and red light resulted in the lowest light use efficiency (29 g m 2 d 1). Presumed signs of biological interference caused by employing monochromatic light of various wavelengths are discussed. This study provides a base for different approaches to maximize productivity by lowering the biomass specific light absorption rate.

Keywords

Chlamydomonas reinhardtii
Areal biomass productivity
Photosynthetic efficiency
Color of light
Spectral light composition

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