Mechanism of carbon partitioning towards starch and triacylglycerol in Chlorella vulgaris under nitrogen stress through whole-transcriptome analysis

Nordin, Norazela; Yusof, Norjan; Maeda, Takeyasu; Mustapha, Nurul Asyifah; Yusoff, Mohd Zulkhairi Mohd; Khairuddin, Raja Farhana Raja

doi:10.1016/j.biombioe.2020.105600

Cited by 37 publications

(15 citation statements)

References 36 publications

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“…Starch and lipid storage patterns in our study are in agreement with several examples existing in the literature that show how starch accumulation is a fast response to environmental changes, with an anabolic phase lasting 12-48 h followed by starch degradation and concomitant lipid synthesis [63][64][65]. This sequential accumulation is a mechanism that is activated when sub-optimal conditions are long-term, and the cells turn from starch to lipid synthesis, which is preferred as storage having higher energy density and stability [21,66].…”

Section: Chemical Componentssupporting

confidence: 90%

Starch Rich Chlorella vulgaris: High-Throughput Screening and Up-Scale for Tailored Biomass Production

et al. 2021

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The use of microalgal starch has been studied in biorefinery frameworks to produce bioethanol or bioplastics, however, these products are currently not economically viable. Using starch-rich biomass as an ingredient in food applications is a novel way to create more value while expanding the product portfolio of the microalgal industry. Optimization of starch production in the food-approved species Chlorella vulgaris was the main objective of this study. High-throughput screening of biomass composition in response to multiple stressors was performed with FTIR spectroscopy. Nitrogen starvation was identified as an important factor for starch accumulation. Moreover, further studies were performed to assess the role of light distribution, investigating the role of photon supply rates in flat panel photobioreactors. Starch-rich biomass with up to 30% starch was achieved in cultures with low inoculation density (0.1 g L−1) and high irradiation (1800 µmol m−2 s−1). A final large-scale experiment was performed in 25 L tubular reactors, achieving a maximum of 44% starch in the biomass after 12 h in nitrogen starved conditions.

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Section: Chemical Componentssupporting

confidence: 90%

Starch Rich Chlorella vulgaris: High-Throughput Screening and Up-Scale for Tailored Biomass Production

et al. 2021

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“…These results are in contrast with the literature, where overexpression of G6PDH induced an increase in lipid content in P. tricornutum, highlighting its critical role in algal lipid accumulation by enhancing NADPH supply [ 64 ]. However, transcription of G6PDH in nitrogen limitation shows significant differences between green microalgae C. vulgaris [ 65 ], Chlamydomonas reinhardtii [ 66 ], diatom Thalassiosira pseudonana [ 67 ], and Nannochloropsis gaditana (Eustigmatophyceae) [ 68 ]. In fact, modifications at the transcript level of the gene G6PDH suggest that PPP is less active in N− conditions, indicating that NADPH yield could be produced by another metabolic pattern.…”

Section: Resultsmentioning

confidence: 99%

Culture Conditions Affect Antioxidant Production, Metabolism and Related Biomarkers of the Microalgae Phaeodactylum tricornutum

et al. 2022

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Phaeodactylum tricornutum (Bacillariophyta) is a worldwide-distributed diatom with the ability to adapt and survive in different environmental habitats and nutrient-limited conditions. In this research, we investigated the growth performance, the total lipids productivity, the major categories of fatty acids, and the antioxidant content in P. tricornutum subjected for 15 days to nitrogen deprivation (N-) compared to standard culture conditions (N+). Furthermore, genes and pathways related to lipid biosynthesis (i.e., glucose-6-phosphate dehydrogenase, acetyl-coenzyme A carboxylase, citrate synthase, and isocitrate dehydrogenase) and photosynthetic activity (i.e., ribulose-1,5-bisphospate carboxylase/oxygenase and fucoxanthin-chlorophyll a/c binding protein B) were investigated through molecular approaches. P. tricornutum grown under starvation condition (N-) increased lipids production (42.5 ± 0.19 g/100 g) and decreased secondary metabolites productivity (phenolic content: 3.071 ± 0.17 mg GAE g-1; carotenoids: 0.35 ± 0.01 mg g−1) when compared to standard culture conditions (N+). Moreover, N deprivation led to an increase in the expression of genes involved in fatty acid biosynthesis and a decrease in genes related to photosynthesis. These results could be used as indicators of nitrogen limitation for environmental or industrial monitoring of P. tricornutum.

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“…[ 35 , 36 ], respectively. Only 2.1% of floridean starch was found in a commercial P. purpureum sample [ 29 ] but levels might be higher under different growth conditions, as seen for C. vulgaris [ 37 , 38 ]. Indeed, low levels (0–14%) of α-linked glucose were found in commercial Chlorella sp.…”

Section: Resultsmentioning

confidence: 99%

Nutritional Profiling and Preliminary Bioactivity Screening of Five Micro-Algae Strains Cultivated in Northwest Europe

Verspreet

Soetemans

Gargan

et al. 2021

Foods

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This study aimed to map the nutritional profile and bioactivities of five microalgae that can be grown in Northwest Europe or areas with similar cultivation conditions. Next to the biochemical composition, the in vitro digestibility of carbohydrates, proteins, and lipids was studied for Chlamydomonas nivalis, Porphyridium purpureum, Chlorella vulgaris, Nannochloropsis gaditana, and Scenedesmus species biomass. These microalgae were also assessed for their ability to inhibit the angiotensin-1-converting enzyme (ACE-1, EC 3.4.15.1), which is known to play a role in the control of blood pressure in mammals. Large differences in organic matter solubility after digestion suggested that a cell disruption step is needed to unlock the majority of the nutrients from N. gaditana and Scenedesmus species biomass. Significant amounts of free glucose (16.4–25.5 g glucose/100 g dry algae) were detected after the digestion of C. nivalis, P. purpureum, and disrupted Scenedesmus. The fatty acid profiles showed major variations, with particularly high Ω-3 fatty acid levels found in N. gaditana (5.5 ± 0.5 g/100 g dry algae), while lipid digestibility ranged from 33.3 ± 6.5% (disrupted N. gaditana) to 67.1 ± 11.2% (P. purpureum). C. vulgaris and disrupted N. gaditana had the highest protein content (45–46% of dry matter), a nitrogen solubility after digestion of 65–71%, and the degree of protein hydrolysis was determined as 31% and 26%, respectively. Microalgae inhibited ACE-1 by 73.4–87.1% at physiologically relevant concentrations compared to a commercial control. These data can assist algae growers and processors in selecting the most suitable algae species for food or feed applications.

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Mechanism of carbon partitioning towards starch and triacylglycerol in Chlorella vulgaris under nitrogen stress through whole-transcriptome analysis

Cited by 37 publications

References 36 publications

Starch Rich Chlorella vulgaris: High-Throughput Screening and Up-Scale for Tailored Biomass Production

Starch Rich Chlorella vulgaris: High-Throughput Screening and Up-Scale for Tailored Biomass Production

Culture Conditions Affect Antioxidant Production, Metabolism and Related Biomarkers of the Microalgae Phaeodactylum tricornutum

Nutritional Profiling and Preliminary Bioactivity Screening of Five Micro-Algae Strains Cultivated in Northwest Europe

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