Initial Investigations of a Shallow-Layer Algal Production System

1979 ◽  
Author(s):  
L. P. Raymond
Keyword(s):  
Photosynthetically Active Radiation ◽  
Phaeodactylum Tricornutum ◽  
Photosynthetic Efficiency ◽  
Culture Media ◽  
Marine Diatom ◽  
Foam Fractionation ◽  
Total Solar Radiation ◽  
Full Potential ◽  
Active Radiation ◽  
Bio Engineering

A system for the intensive cultivation of the marine diatom Phaeodactylum tricornutum is described and evaluated. Unique features of the system include: (a) the incorporation of solar heat collection device which transmits only photosynthetically active radiation (PAR) to the growing culture; (b) the formulation of a new seawater enrichment medium that promotes physiological responses not previously observed in culture; and (c) the use of a foam fractionation device which separates microalgae, from the culture media, adds CO2-enriched air, and/or simultaneously recirculates the growing culture in shallow layers through an interconnecting series of hemicylindrical channels. The outdoor system demonstrated that very high ash-free dry weight yields of Phaeodactylum tricornutum are produced, a result of high photosynthetic efficiency. Actual yield over an eight-day period was equivalent to 39.57 ash-free dry tons/acre-year. Observed photosynthetic efficiency, based on photosynthetically active radiation incident upon the external surface of the system, is 13.1 percent, nearly three times the limit previously considered economically practical. The data indicate that greater yields may be expected using this system at locations receiveing higher insolation. A conservative projection is that 80 ash-free dry tons/acre-year will be realized in land regions receiveing 3 × 1010 Btu/acre-year total solar radiation. It is concluded that this system clearly warrants further investigation to determine its capacity to produce large and economical quantities of algal biomass for use as potential petroleum-fuel substitutes. The development of a comprehensive and systematic bio-engineering program is recommended to upgrade and evaluate the system to its full potential.

Physiological performance of a foliose macrolichen Umbilicaria antarctica as affected by supplemental UV-B treatment

2015 ◽  
Vol 5 (2) ◽  
pp. 222-229 ◽  
Author(s):  
Mariana Gonzalez Medina ◽  
Roxana Avalos-Chacon
Keyword(s):  
Chlorophyll Fluorescence ◽  
High Resistance ◽  
Photosynthetically Active Radiation ◽  
High Intensity ◽  
Photosynthetic Efficiency ◽  
Photosynthetic Apparatus ◽  
Ps Ii ◽  
Fluorescence Kinetics ◽  
Active Radiation ◽  
High Doses

To date, a limited knowledge is available about Umbilicaria antarctica responses when it is exposed high doses of UV-B radiation. It is well established that resistance of Antarctic lichens to natural UV-B levels including increased doses during ozone hole period is high, thanks to numerous photoprotective mechanism. Capacity of the photoprotective processes, however, is not well known This study attempts to determine changes on the photosynthetic efficiency and on the synthesis of UV-B absorbing compounds of U. antarctica when exposed to low photosynthetically active radiation and extremely high intensity of UV-B light: 3.0 W m-2, of UV-B for 3 hours, 6 hours and 7 days. During the experiment, chlorophyll fluorescence was measured to evaluate changes in photosynthetic apparatus of intrathalline alga. After 7 d exposition, amount of UV-B absorbing compounds was evaluated in U. antarctica. Heavy UV-B stress let to an increase in chlorophyll fluorescence kinetics (OJIPs), however, majority of parameters related to functioning of PS II remained unchanged indicating high resistance of U. antarctica to UV-B stress. Potential (FV/FM) and actual (ФPSII) yields of PS II were not affected by the UV-B treatment as well. In majority of cases, heavy UV-B treatment led to a decrease in the amount of UV-B absorbing compounds extracted from treated thalli.

scholarly journals Bacterial diketopiperazines stimulate diatom growth and lipid accumulation

2021 ◽  
Author(s):  
John Sittmann ◽  
Munhyung Bae ◽  
Emily Mevers ◽  
Muzi Li ◽  
Andrew Quinn ◽  
...  
Keyword(s):  
Lipid Content ◽  
Phaeodactylum Tricornutum ◽  
Photosynthetic Efficiency ◽  
Biofuel Production ◽  
Marine Diatom ◽  
Diatom Cell ◽  
Marine Microbes ◽  
Bacillus Cereus Group ◽  
Cell Lysate ◽  
High Lipid

Abstract Diatoms are photosynthetic microalgae that fix a significant fraction of the world’s carbon. Because of their photosynthetic efficiency and high-lipid content, diatoms are priority candidates for biofuel production. Here, we report that sporulating Bacillus thuringiensis and other members of the Bacillus cereus group, when in co-culture with the marine diatom Phaeodactylum tricornutum, significantly increase diatom cell count. Bioassay-guided purification of the mother cell lysate of B. thuringiensis led to the identification of two diketopiperazines (DKPs) that both stimulate P. tricornutum growth and increase its lipid content. These findings may be exploited to enhance P. tricornutum growth and microalgae-based biofuel production. As increasing numbers of DKPs are isolated from marine microbes, the work gives potential clues to bacterial-produced growth factors for marine microalgae.

scholarly journals Thylakoid luminal θ-carbonic anhydrase critical for growth and photosynthesis in the marine diatom Phaeodactylum tricornutum

2016 ◽  
Vol 113 (35) ◽  
pp. 9828-9833 ◽  
Author(s):  
Sae Kikutani ◽  
Kensuke Nakajima ◽  
Chikako Nagasato ◽  
Yoshinori Tsuji ◽  
Ai Miyatake ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Phaeodactylum Tricornutum ◽  
Photosynthetic Efficiency ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Marine Diatom ◽  
Bisphosphate Carboxylase ◽  
Gfp Fusion Protein ◽  
Close Proximity ◽  
Esterase Activities

The algal pyrenoid is a large plastid body, where the majority of the CO2-fixing enzyme, ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) resides, and it is proposed to be the hub of the algal CO2-concentrating mechanism (CCM) and CO2 fixation. The thylakoid membrane is often in close proximity to or penetrates the pyrenoid itself, implying there is a functional cooperation between the pyrenoid and thylakoid. Here, GFP tagging and immunolocalization analyses revealed that a previously unidentified protein, Pt43233, is targeted to the lumen of the pyrenoid-penetrating thylakoid in the marine diatom Phaeodactylum tricornutum. The recombinant Pt43233 produced in Escherichia coli cells had both carbonic anhydrase (CA) and esterase activities. Furthermore, a Pt43233:GFP-fusion protein immunoprecipitated from P. tricornutum cells displayed a greater specific CA activity than detected for the purified recombinant protein. In an RNAi-generated Pt43233 knockdown mutant grown in atmospheric CO2 levels, photosynthetic dissolved inorganic carbon (DIC) affinity was decreased and growth was constantly retarded; in contrast, overexpression of Pt43233:GFP yielded a slightly greater photosynthetic DIC affinity. The discovery of a θ-type CA localized to the thylakoid lumen, with an essential role in photosynthetic efficiency and growth, strongly suggests the existence of a common role for the thylakoid-luminal CA with respect to the function of diverse algal pyrenoids.

scholarly journals A microbiota–root–shoot circuit favours Arabidopsis growth over defence under suboptimal light

Nature Plants ◽  
2021 ◽  
Author(s):  
Shiji Hou ◽  
Thorsten Thiergart ◽  
Nathan Vannier ◽  
Fantin Mesny ◽  
Jörg Ziegler ◽  
...  
Keyword(s):  
Stress Responses ◽  
Photosynthetically Active Radiation ◽  
Bacterial Community Composition ◽  
Light Condition ◽  
Long Distance ◽  
Active Radiation ◽  
Light Manipulation ◽  
Growth Deficiency ◽  
Dependent Growth ◽  
Control Light

AbstractBidirectional root–shoot signalling is probably key in orchestrating stress responses and ensuring plant survival. Here, we show that Arabidopsis thaliana responses to microbial root commensals and light are interconnected along a microbiota–root–shoot axis. Microbiota and light manipulation experiments in a gnotobiotic plant system reveal that low photosynthetically active radiation perceived by leaves induces long-distance modulation of root bacterial communities but not fungal or oomycete communities. Reciprocally, microbial commensals alleviate plant growth deficiency under low photosynthetically active radiation. This growth rescue was associated with reduced microbiota-induced aboveground defence responses and altered resistance to foliar pathogens compared with the control light condition. Inspection of a set of A. thaliana mutants reveals that this microbiota- and light-dependent growth–defence trade-off is directly explained by belowground bacterial community composition and requires the host transcriptional regulator MYC2. Our work indicates that aboveground stress responses in plants can be modulated by signals from microbial root commensals.

scholarly journals Intercepted Photosynthetically Active Radiation (PAR) and Spatial and Temporal Distribution of Transmitted PAR under High-Density and Super High-Density Olive Orchards

Agriculture ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 351
Author(s):  
Adolfo Rosati ◽  
Damiano Marchionni ◽  
Dario Mantovani ◽  
Luigi Ponti ◽  
Franco Famiani
Keyword(s):  
Spatial Variability ◽  
Photosynthetically Active Radiation ◽  
Temporal Distribution ◽  
High Density ◽  
Radiation Use Efficiency ◽  
Spatial And Temporal Distribution ◽  
Active Radiation ◽  
Use Efficiency ◽  
And Performance ◽  
Radiation Use

We quantified the photosynthetically active radiation (PAR) interception in a high-density (HD) and a super high-density (SHD) or hedgerow olive system, by measuring the PAR transmitted under the canopy along transects at increasing distance from the tree rows. Transmitted PAR was measured every minute, then cumulated over the day and the season. The frequencies of the different PAR levels occurring during the day were calculated. SHD intercepted significantly but slightly less overall PAR than HD (0.57 ± 0.002 vs. 0.62 ± 0.03 of the PAR incident above the canopy) but had a much greater spatial variability of transmitted PAR (0.21 under the tree row, up to 0.59 in the alley center), compared to HD (range: 0.34–0.43). This corresponded to greater variability in the frequencies of daily PAR values, with the more shaded positions receiving greater frequencies of low PAR values. The much lower PAR level under the tree row in SHD, compared to any position in HD, implies greater self-shading in lower-canopy layers, despite similar overall interception. Therefore, knowing overall PAR interception does not allow an understanding of differences in PAR distribution on the ground and within the canopy and their possible effects on canopy radiation use efficiency (RUE) and performance, between different architectural systems.

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