Flashing LEDs for Microalgal Production

Abstract

Flashing lights are next-generation tools to mitigate light attenuation and increase the photosynthetic efficiency of microalgal cultivation systems illuminated by light-emitting diodes (LEDs). Optimal flashing light conditions depend on the reaction kinetics and properties of the linear electron transfer chain, energy dissipation, and storage mechanisms of a phototroph. In particular, extremely short and intense light flashes potentially mitigate light attenuation in photobioreactors without impairing photosynthesis. Intelligently controlling flashing light units and selecting electronic components can maximize light emission and energy efficiency. We discuss the biological, physical, and technical properties of flashing lights for algal production. We combine recent findings about photosynthetic pathways, self-shading in photobioreactors, and developments in solid-state technology towards the biotechnological application of LEDs to microalgal production.

Combined effect of nutrient and flashing light frequency for a biochemical composition shift in Nannochloropsis gaditana grown in a quasi‐isoactinic reactor

“…The flashing light effect has been widely studied in the literature, as reviewed by some authors. [25,26] Several authors found a correlation between the flashing frequency and the growth performance. For example, similarly to in the present work, Vejrazka and co-workers [27] observed in Chlamydomonas reinardtii that specific growth rate decreased from continuous light to flashing light and increased by increasing the flashing frequency (DC = 0.1, f = 5-100 Hz).…”

Influence of Photoperiods on Microalgae Biofilm: Photosynthetic Performance, Biomass Yield, and Cellular Composition

“…Because of their fast growth rate, low nutrient requirements, and high lipid contents, microalgae have immense potential as biological sources to produce biofuels, high-value biomolecules, and feeds [1][2][3][4]. Unfortunately, at present, the energy requirements and costs of microalgae-based commodities are still relatively high, which hinders their broad commercialization [5][6][7]. Recently, several studies have reported that cultivating microalgae as biofilm (where cells are attached to a solid surface) can substantially reduce energy requirement and enhance economic feasibility of microalgae-based biorefineries, owing to the high photosynthetic efficiency, high biomass productivity, 2 of 10 and low cost of harvesting [8][9][10][11][12].…”

“…Generally, light-related parameters in microalgae cultivation include light intensity, light spectrum, photoperiod, source of illumination, light-switching strategy, and direction of light [11,[15][16][17]. Among them, photoperiod plays an important role in microalgal photosynthesis and growth [6,15,18,19].…”

Exergy efficiency of light conversion into biomass in the macroalga Ulva sp. (Chlorophyta) cultivated under the pulsed light in a photobioreactor

“…growth under the pulsed light. Although biomass growth of plant and microalgae under pulsed light has been reported before (Gris, Morosinotto, Giacometti, Bertucco, & Sforza, ; Nedbal, Tichý, Xiong, & Grobbelaar, ; Tennessen et al, ), most recently reviewed in (Schulze, Guerra, Pereira, Schüler, & Varela, ), to the best of our knowledge there are no reports on macroalgae, and specifically of Ulva species, grown under pulsed light. These data will be of importance not only for a fundamental understanding of algal metabolism under the pulsed light but it will also enable a rational design of macroalgal cultivation in photobioreactors both onshore and offshore cultivation.…”

“…growth under the pulsed light. Although biomass growth of plant and microalgae under pulsed light has been reported before (Gris, Morosinotto, Giacometti, Bertucco, & Sforza, 2014;Nedbal, Tichý, Xiong, & Grobbelaar, 1996;Tennessen et al, 1995), most recently reviewed in (Schulze, Guerra, Pereira, Schüler, & Varela, 2017), to the best of our knowledge there are no reports on macroalgae, and specifically of Ulva species, grown under pulsed light.…”