Microalgal biofilm growth under day-night cycles

Blanken, Ward; Magalhaes, Ana Martins Pito de; Sebestyén, Petra; Rinzema, A.; Wijffels, René H.; Janssen, Marcel

doi:10.1016/j.algal.2016.11.006

Cited by 18 publications

(4 citation statements)

References 30 publications

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“…During the night, respiration takes over and the particle resurfaces and stays at the surface until the light reappears and the biofilm has grown enough to start settling again. Circadian cycles, or 24 h cycles, have been observed in algal behavior, where an increase in chlorophyll- a concentrations is observed during the day, while a decrease is found during dark hours. − The circadian cycles observed in algal growth can be considered a good proxy for biofilm driven microplastic circadian cycles as simulated in this study (Figure a, Figure S1).…”

Section: Results and Discussionmentioning

confidence: 60%

Ups and Downs in the Ocean: Effects of Biofouling on Vertical Transport of Microplastics

Kooi

Nes

Scheffer

et al. 2017

Environ. Sci. Technol.

720

449

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Recent studies suggest size-selective removal of small plastic particles from the ocean surface, an observation that remains unexplained. We studied one of the hypotheses regarding this size-selective removal: the formation of a biofilm on the microplastics (biofouling). We developed the first theoretical model that is capable of simulating the effect of biofouling on the fate of microplastic. The model is based on settling, biofilm growth, and ocean depth profiles for light, water density, temperature, salinity, and viscosity. Using realistic parameters, the model simulates the vertical transport of small microplastic particles over time, and predicts that the particles either float, sink to the ocean floor, or oscillate vertically, depending on the size and density of the particle. The predicted size-dependent vertical movement of microplastic particles results in a maximum concentration at intermediate depths. Consequently, relatively low abundances of small particles are predicted at the ocean surface, while at the same time these small particles may never reach the ocean floor. Our results hint at the fate of “lost” plastic in the ocean, and provide a start for predicting risks of exposure to microplastics for potentially vulnerable species living at these depths.

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Section: Results and Discussionmentioning

confidence: 60%

Ups and Downs in the Ocean: Effects of Biofouling on Vertical Transport of Microplastics

Kooi

Nes

Scheffer

et al. 2017

Environ. Sci. Technol.

720

449

View full text Add to dashboard Cite

show abstract

“…Other studies however reported that part of the carbon accumulated during the day in the form of starch or lipids, is consumed during the night for protein synthesis. 13,45 Even so, whether or not protein synthesis occurs during the night is unclear and goes beyond the scope of this study. Neither mixotrophic or autotrophic cultures expressed significant nitrogen uptake during the night, and we can safely conclude that night time nitrogen uptake is not affected by mixotrophy.…”

Section: Table 2 Average Mixotrophic and Autotrophic Specific Oxygenmentioning

confidence: 99%

Oxygen Balanced Mixotrophy under Day–Night Cycles

Abiusi

Wijffels

Janssen

2020

ACS Sustainable Chem. Eng.

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Using sunlight to fuel photosynthesis exposes microalgae to day−night cycles. Under day−night cycles microalgae tend to synchronize their metabolism by optimizing light utilization during daytime. During night storage compounds are consumed, leading to biomass losses and demand of O 2 . We investigated "oxygen balanced" mixotrophy under 14:10 day/night cycles. In this mixotrophic setup, photosynthetic O 2 production was balanced by respiratory oxygen consumption and CO 2 required for photosynthesis was provided by aerobic conversion of acetic acid. This strategy allowed operation of the reactor without any gas−liquid exchange during daytime. Under these conditions Chlorella sorokiniana SAG 211/8K converted 96% of the substrate into biomass. Mixotrophic cultivation did not affect the photosystem II maximum quantum yield (Fv/Fm) or pigment contents of the microalgal cells. Mixotrophic biomass contained 50% w/w of protein and 7.3 mg g −1 of lutein. Acetic acid feeding was discontinued at night and aeration initiated. Respiration was monitored by online off-gas analysis and O 2 consumption and CO 2 production rates were determined. Biomass night losses were around 7% on carbon basis with no significant difference between mixotrophic and photoautotrophic cultures. Over 24 h, the mixotrophic culture required 61 times less gaseous substrate and its biomass productivity was doubled compared to the photoautotrophic counterpart.

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“…Overnight losses in biomass and starch are similar ( Supplementary Table S5.2). This supports the hypothesis that starch is respired overnight, as also observed in other diurnal studies on photosynthetic organisms (Blanken et al, 2017).…”

Section: Biomass Composition Of a Obliquus Wildtype Fluctuates Throusupporting

confidence: 91%

Photosynthetic efficiency in microalgal lipid production

Remmers¹

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Lipid production in microalgae is highly dependent on the applied light intensity. However, for the EPA producing model-diatom Phaeodactylum tricornutum, clear consensus on the impact of incident light intensity on lipid productivity is still lacking. This study quantifies the impact of different incident light intensities on the biomass, TAG and EPA yield on light in nitrogen starved batch cultures of P. tricornutum. The maximum biomass concentration and maximum TAG and EPA contents were found to be independent of the applied light intensity. The lipid yield on light was reduced at elevated light intensities (>100 µmol m-2 s-1). The highest TAG yield on light (112 mg TAG molph-1) was found at the lowest light intensity tested (60 µmol m-2 s-1), which is still relatively low to values reported in literature for other algae. Furthermore, mass balance analysis showed that the EPA fraction in TAG may originate from photosynthetic membrane lipids.

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Microalgal biofilm growth under day-night cycles

Cited by 18 publications

References 30 publications

Ups and Downs in the Ocean: Effects of Biofouling on Vertical Transport of Microplastics

Ups and Downs in the Ocean: Effects of Biofouling on Vertical Transport of Microplastics

Oxygen Balanced Mixotrophy under Day–Night Cycles

Photosynthetic efficiency in microalgal lipid production

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