Interactive effect of light quality and temperature on Chlamydomonas reinhardtii growth kinetics and lipid synthesis

Li, Xiangpeng; Slavens, Shelyn; Crunkleton, Daniel W.; Johannes, Tyler W.

doi:10.1016/j.algal.2020.102127

Cited by 33 publications

(5 citation statements)

References 71 publications

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“…This could generally indicate that with an increase in enzymatic efficiency at elevated temperatures, there may be lower requirements for metal‐requiring protein/enzyme content in general (as indicated by the S content) and less requirements for storage sites like vacuoles (as indicated from P, Ca reduction). Studies have shown that in various algal species, including C. reinhardtii , increasing cultivation temperature results in modulation of the fatty acid profile, which is not reflected in the total cellular C content, and lipid accumulation, which might contribute to maintaining the C content specifically (James et al., 2013; Li et al., 2021; Lukeš et al., 2014; Morales‐Sánchez et al., 2020).…”

Section: Discussionmentioning

confidence: 99%

Simple steps to enable reproducibility: culture conditions affecting Chlamydomonas growth and elemental composition

et al. 2022

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SUMMARY Even subtle modifications in growth conditions elicit acclimation responses affecting the molecular and elemental makeup of organisms, both in the laboratory and in natural habitats. We systematically explored the effect of temperature, pH, nutrient availability, culture density, and access to CO2 and O2 in laboratory‐grown algal cultures on growth rate, the ionome, and the ability to accumulate Fe. We found algal cells accumulate Fe in alkaline conditions, even more so when excess Fe is present, coinciding with a reduced growth rate. Using a combination of Fe‐specific dyes, X‐ray fluorescence microscopy, and NanoSIMS, we show that the alkaline‐accumulated Fe was intracellularly sequestered into acidocalcisomes, which are localized towards the periphery of the cells. At high photon flux densities, Zn and Ca specifically over‐accumulate, while Zn alone accumulates at low temperatures. The impact of aeration was probed by reducing shaking speeds and changing vessel fill levels; the former increased the Cu quota of cultures, the latter resulted in a reduction in P, Ca, and Mn at low fill levels. Trace element quotas were also affected in the stationary phase, where specifically Fe, Cu, and Zn accumulate. Cu accumulation here depends inversely on the Fe concentration of the medium. Individual laboratory strains accumulate Ca, P, and Cu to different levels. All together, we identified a set of specific changes to growth rate, elemental composition, and the capacity to store Fe in response to subtle differences in culturing conditions of Chlamydomonas, affecting experimental reproducibility. Accordingly, we recommend that these variables be recorded and reported as associated metadata.

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Section: Discussionmentioning

confidence: 99%

Simple steps to enable reproducibility: culture conditions affecting Chlamydomonas growth and elemental composition

et al. 2022

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“…(ii) Light quality was investigated for example in the chlorophyte Chlamydomonas reinhardtii and showed different lipid accumulation depending on the wavelength, using blue, white-yellow, or red-orange light. For this Chlorophyte the red-orange light resulted in highest biomass accumulation and favored lipid accumulation (Li et al 2021). In line with this study, in a P. tricornutum strain red light also promoted biomass production.…”

Section: Lightsupporting

confidence: 88%

Towards the usage of Phaeodactylum tricornutum as biofactory for omega-3 fatty acids

Krämer¹

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The increasing demand of the high value ω-3 fatty acids due to its beneficial role for human health, explains the huge need for alternative production ways of ω-3 fatty acids. The oleaginous alga Phaeodactylum tricornutum is a prominent candidate and has been investigated as biofactory for ω-3 fatty acids, e.g. the synthesis of eicosapentaenoic acid (EPA). In general, the growth and the lipid content of diatoms can be enhanced by genetic engineering or are influenced by environmental factors, e.g. nutrients, light or temperature. In this study, the potential of P. tricornutum as biofactory was improved by heterologously expressing the hexose uptake protein 1 (HUP1) from the Chlorophyte Chlorella kessleri. An in situ localization study revealed that only the full length HUP1 protein fused to eGFP was correctly targeted to the plasma membrane, whereas the N-terminal sequence of the protein is only sufficient to enter the ER. Protein and gene expression data displayed that the gene-promoter combination was relevant for the expression level of HUP1, while only cells expressing the protein under the light-inducible fcpA promoter showed a significant expression. In these mutants an efficient glucose uptake was detectable under mixotrophic growth condition, low light intensities and low glucose concentrations leading to an increased cell dry weight. In a second approach, the growth and lipid content of wildtype cells were analyzed in a small 1l photobioreactor. Here, a commercial F/2 medium and a common culture medium, ASP and modified versions were compared. There was neither a significant impact on the growth and lipid content in P. tricornutum cells due to the supplemention of trace elements nor due to elevated salt concentrations in the media. In a modified version of ASP medium, with adapted nitrate and phosphate concentration a constantly high biomass productivity was achieved, yielding the highest value of 82 mg l-1 d-1 during the first three days. This was achieved even though light intensity was reduced by 40%. The differences in biomass productivity as well as the lipid content and the lipid composition underlined the importance of the choice of culture medium and the harvest time for enhanced growth and EPA yields in P. tricornutum.

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“…This method is widely used in the neutral lipid content check and has been proved to be a rapid and accurate method (Kou et al, 2013;Rumin et al, 2015;Velmurugan et al, 2013). The application of NR staining method on the lipid content measurement of C. reinhardtii was studied in detail in our previous work (Li et al, 2021). Briefly, algae culture was centrifuged and washed with DDW; algae pellets remained or the algae pellets stored were resuspended with DDW with a dilution factor of 2; 5 ml dilution was added to a 10-ml glass tube and then dimethyl sulfoxide (DMSO) and NR stock solutions were added with a final concentration of 3% (v/v) and 0.7 mg/L respectively; samples were vortexed vigorously for sufficient mixing; 300 µl of algae samples and the triolein standard solutions were pipetted to a 96-well optical plate and measured at the same time; and fluorescence of NR mixture was checked on a fluorometer (Tecan Safire A-5082 Austria) with an excitation wavelength of 530 nm and an emission wavelength of 580 nm.…”

Section: Nutrient Composition Measurement Methodsmentioning

confidence: 99%

Variation of nutrient profile inChlamydomonas reinhardtiiduring storage at four typical temperatures

Crunkleton

Johannes

2021

Aquaculture Research

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Post-harvest loss during storage and processing must be minimized to maintain algal nutrient value and enhance nutrient recovery. The lipid content, in particular, is of great concern due to its major role in the nutrient evaluation and biofuel applications. In this study, the degradation of neutral lipids in the green alga Chlamydomonas reinhardtii was investigated under storage at four temperatures (−80°C, −20°C, 4°C and 20°C). Preservation with concentrated algae paste or with culture was tested.Contrary to the slow lipid degradation rate observed in previous work, the present study shows a rapid lipid degradation rate. Within the first 24 hours, the lipid concentration declined 45% and 60% during storage as culture at 4°C and 20°C, respectively, and declined 73%, 74%, 48% and 69% during storage as pellets at −80°C, −20°C, 4°C and 20°C respectively. The degradation rate of protein and carbohydrate was also determined. Based on our results, the preferred storage method for lipid is dark sealed cooling, for protein is freezing or cooling and for carbohydrate is freezing with algal paste.

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Interactive effect of light quality and temperature on Chlamydomonas reinhardtii growth kinetics and lipid synthesis

Cited by 33 publications

References 71 publications

Simple steps to enable reproducibility: culture conditions affecting Chlamydomonas growth and elemental composition

Simple steps to enable reproducibility: culture conditions affecting Chlamydomonas growth and elemental composition

Towards the usage of Phaeodactylum tricornutum as biofactory for omega-3 fatty acids

Variation of nutrient profile inChlamydomonas reinhardtiiduring storage at four typical temperatures

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