Application of light‐emitting diodes in bioreactors: Flashing light effects and energy economy in algal culture (Chlorella pyrenoidosa)

Matthijs, H.C.P.; Balke, Hans; Hes, Udo M. van; Kroon, Bernd M. A.; Mur, Luuc R.; Binot, Roger A.

doi:10.1002/(sici)1097-0290(19960405)50:1<98::aid-bit11>3.3.co;2-9

Cited by 38 publications

(60 citation statements)

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“…In some cases of fast cycles, full light integration has been shown, meaning that cells use flashing light and continuous light (of equal average intensity) with the same efficiency (Grobbelaar et al, ; Kok, ; Matthijs et al, ; Nedbal et al, ; Phillips and Myers, ; Terry, ). Nevertheless, the threshold for this full light integration is not well defined as flash frequencies from 5 Hz to 1 kHz have been reported (Kok, ; Matthijs et al, ; Terry, ). This range of time scales is representative of photobioreactors conditions, and the effect of light fluctuation within a less intensively agitated raceway is less documented.…”

Section: Introductionmentioning

confidence: 99%

Long‐term adaptive response to high‐frequency light signals in the unicellular photosynthetic eukaryote Dunaliella salina

Combe

Hartmann

Rabouille

et al. 2015

Biotech & Bioengineering

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Productivity of microalgal cultivation processes is tightly related to photosynthetic efficiency, and therefore to light availability at the cell scale. In an agitated, highly turbid suspension,the light signal received by a single phytoplankton cell moving in a dense culture is a succession of flashes. The growth characteristics of microalgae under such dynamic light conditions are thus fundamental information to understand nonlinear properties of the photosynthetic process and to improve cultivation process design and operation. Studies of the long term consequences of dynamic illumination regime on photosynthesis require a very specific experimental set-up where fast varying signals are applied on the long term. In order to investigate the growth response of the unicellular photosynthetic eukaryote Dunaliella salina (Chlorophyceae) to intermittent light exposure, different light regimes using LEDs with the same average total light dose were applied in continuous cultures. Flashing light with different durations of light flashes (△t of 30 s, 15 s, 2 s and 0.1 s) followed by dark periods of variable length (0.67 ≤ L:D ≤ 2) yielding flash frequencies in the range 0.017-5 Hz, were compared to continuous illumination. Specific growth rate, photosynthetic pigments, lipid productivity and elemental composition were measured on two duplicates for each irradiance condition. The different treatments of intermittent light led to specific growth rates ranging from 0.25 to 0.93 day(-1) . While photosynthetic efficiency was enhanced with increased flash frequency, no significant differences were observed in the particular carbon and chlorophyll content. Pigment analysis showed that within this range of flash frequency, cells progressively photoacclimated to the average light intensity.

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Section: Introductionmentioning

confidence: 99%

Long‐term adaptive response to high‐frequency light signals in the unicellular photosynthetic eukaryote Dunaliella salina

Combe

Hartmann

Rabouille

et al. 2015

Biotech & Bioengineering

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“…Algae response to different (dynamic) light regimes was studied by photosynthetic rate measurements based on oxygen evolution rate (Kok and Burlew, 1953; Matthijs et al, 1996; Nedbal et al, 1996; Terry, 1986) or specific growth rate (Phillips and Myers, 1954; Rosello‐Sastre, 2010; Vejrazka et al, 2011; Xue et al, 2011). These photosynthetic rate measurements (oxygen evolution rate and growth rate) showed that sub‐second L/D cycles are necessary to measure light integration.…”

Section: Introductionmentioning

confidence: 99%

Photosynthetic efficiency of Chlamydomonas reinhardtii in attenuated, flashing light

Vejrazka

Janssen

Streefland

et al. 2012

Biotech & Bioengineering

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As a result of mixing and light attenuation, algae in a photobioreactor (PBR) alternate between light and dark zones and, therefore, experience variations in photon flux density (PFD). These variations in PFD are called light/dark (L/D) cycles. The objective of this study was to determine how these L/D cycles affect biomass yield on light energy in microalgae cultivation. For our work, we used controlled, short light path, laboratory, turbidostat-operated PBRs equipped with a LED light source for square-wave L/D cycles with frequencies from 1 to 100 Hz. Biomass density was adjusted that the PFD leaving the PBR was equal to the compensation point of photosynthesis. Algae were acclimated to a sub-saturating incident PFD of 220 µmol m(-2) s(-1) for continuous light. Using a duty cycle of 0.5, we observed that L/D cycles of 1 and 10 Hz resulted on average in a 10% lower biomass yield, but L/D cycles of 100 Hz resulted on average in a 35% higher biomass yield than the yield obtained in continuous light. Our results show that interaction of L/D cycle frequency, culture density and incident PFD play a role in overall PBR productivity. Hence, appropriate L/D cycle setting by mixing strategy appears as a possible way to reduce the effect that dark zone exposure impinges on biomass yield in microalgae cultivation. The results may find application in optimization of outdoor PBR design to maximize biomass yields.

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“…For instance, iron is an essential component of photosynthetic and respiratory electron transport chain, and manganese catalyses the oxygen evolution in the photosynthesis (Matthijs et al . ; Li et al . ; Kumar et al .…”

Section: Resultsmentioning

confidence: 99%

Enhanced growth rate and lipid production of freshwater microalgae by adopting two‐stage cultivation system under diverse light and nutrients conditions

Rashid

Rehman

Han

2015

Water & Environment J

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This study aims to investigate the growth behaviour and lipid production of Chlorella vulgaris (a microalga) by manipulating the effect of light and nutrients. In our presumptive two-staged growth model, C. vulgaris was first grown under low levels of light and nutrients in stage 1 and then in stage 2 under several combinations of light and nutrients, Nt−/Lt− minimum nutrients and minimum light as control; Nt+/Lt+ maximum light and maximum nutrients; Nt+/Lt− maximum nutrients and minimum light, and Nt−/Lt+ minimum nutrients and maximum light. Doubling time reduced from 46.8 ± 02 hours in control (Nt−/Lt−) to 36.1 ± 04 in Nt−/ Lt+ and 37.7 ± 0.9 in Nt+/Lt− and further down to 25.2 ± 03 h in Nt+/Lt+. The highest lipid contents were found in Nt−/Lt+ (9.5 ± 0.14%) followed by Nt+/Lt+ (8.6 ± 0.2%), Nt+/Lt− (6.4 ± 0.12%) and Nt−/Lt− (6.1 ± 0.22%), respectively. The maximum biomass (909 mg/L) was found in Nt+/Lt+ likely suggesting that limited growth in control was attributed to the limitation of nutrients and light. Incremental addition of light and nutrients is suggested for enhanced growth rate, biomass and lipid production.

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Application of light‐emitting diodes in bioreactors: Flashing light effects and energy economy in algal culture (Chlorella pyrenoidosa)

Cited by 38 publications

References 0 publications

Long‐term adaptive response to high‐frequency light signals in the unicellular photosynthetic eukaryote Dunaliella salina

Long‐term adaptive response to high‐frequency light signals in the unicellular photosynthetic eukaryote Dunaliella salina

Photosynthetic efficiency of Chlamydomonas reinhardtii in attenuated, flashing light

Enhanced growth rate and lipid production of freshwater microalgae by adopting two‐stage cultivation system under diverse light and nutrients conditions

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