scholarly journals Enhanced Lipid Production in Chlamydomonas reinhardtii Caused by Severe Iron Deficiency

2021 ◽  
Vol 12 ◽  
Author(s):  
Elsinraju Devadasu ◽  
Rajagopal Subramanyam
Keyword(s):  
Iron Deficiency ◽  
Chlamydomonas Reinhardtii ◽  
Neutral Lipids ◽  
Lipid Production ◽  
Growth Conditions ◽  
Efficient Production ◽  
Control Analysis ◽  
Iron Stress ◽  
Algal Biofuels ◽  
Enhanced Production

Microalgae are used as a source of lipids for the production of biofuels. Most algae produce neutral lipids under stress conditions. Here, lipid accumulation by the unicellular alga Chlamydomonas reinhardtii was examined during cultivation under iron-limiting conditions. Severe iron stress caused the cells to accumulate a significant amount of lipid, specifically triacylglycerols (TAGs), by compromising the growth. Semi-quantitative measurements by Fourier transform infrared (FTIR) spectroscopy showed an increase in both carbohydrate and lipid content in iron-stressed C. reinhardtii cells compared to control. Analysis by flow cytometry and thin layer chromatography confirmed that severe iron deficiency-induced TAG accumulation to fourfold higher than in iron-replete control cells. This accumulation of TAGs was mostly degraded from chloroplast lipids accompanied by overexpression of diacylglycerol acyltransferase (DGAT2A) protein. Furthermore, liquid chromatography-mass spectrometry (LC-MS) analysis demonstrated significantly enhanced levels of C16:0, C18:2, and C18:3 fatty acids (FAs). These results indicate that iron stress triggers the rapid accumulation of TAGs in C. reinhardtii cells. The enhanced production of these lipids caused by the iron deficiency may contribute to the efficient production of algal biofuels if we escalate to the photobioreactor’s growth conditions.

scholarly journals Metabolomic Study of Heterotrophically Grown Chlorella sp. Isolated from Wastewater in Northern Sweden

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2410
Author(s):  
Jean Claude Nzayisenga ◽  
Anita Sellstedt
Keyword(s):  
Sustainable Development ◽  
Butyric Acid ◽  
Lipid Production ◽  
Growth Conditions ◽  
Northern Sweden ◽  
Metabolic Intermediate ◽  
Chlorella Sp ◽  
Lipid Contents ◽  
New Compounds ◽  
Potential Use

There are numerous strains of Chlorella with a corresponding variety of metabolic pathways. A strain we previously isolated from wastewater in northern Sweden can grow heterotrophically as well as autotrophically in light and has higher lipid contents under heterotrophic growth conditions. The aims of the present study were to characterize metabolic changes associated with the higher lipid contents in order to enhance our understanding of lipid production in microalgae and potentially identify new compounds with utility in sustainable development. Inter alia, the amino acids glutamine and lysine were 7-fold more abundant under heterotrophic conditions, the key metabolic intermediate alpha-ketoglutarate was more abundant under heterotrophic conditions with glucose, and maltose was more abundant under heterotrophic conditions with glycerol than under autotrophic conditions. The metabolite 3-hydroxy-butyric acid, the direct precursor of the biodegradable plastic PHB (poly-3-hydroxy-butyric acid), was also more abundant under heterotrophic conditions. Our metabolomic analysis has provided new insights into the alga’s lipid production pathways and identified metabolites with potential use in sustainable development, such as the production of renewable, biodegradable plastics, cosmetics, and nutraceuticals, with reduced pollution and improvements in both ecological and human health.

Cell-wall abnormalities of a Chlamydomonas reinhardtii mutant strain under suboptimal growth conditions

Planta ◽  
1991 ◽  
Vol 183 (1) ◽  
Author(s):  
J�rgen Voigt ◽  
Dieter Mergenhagen ◽  
Irmhild Wachholz ◽  
Elsbeth Manshard ◽  
Marianne Mix
Keyword(s):  
Cell Wall ◽  
Chlamydomonas Reinhardtii ◽  
Mutant Strain ◽  
Growth Conditions

scholarly journals Pigment Production under Cold Stress in the Green Microalga Chlamydomonas reinhardtii

Agriculture ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 564
Author(s):  
Supakorn Potijun ◽  
Chonlada Yaisamlee ◽  
Anchalee Sirikhachornkit
Keyword(s):  
Cold Stress ◽  
Chlamydomonas Reinhardtii ◽  
Production Efficiency ◽  
Cell Physiology ◽  
Efficient Production ◽  
Increase Production Efficiency ◽  
Whole Cells ◽  
Stress Acclimation ◽  
Chlorophyll Accumulation ◽  
In The Wild

Microalgae have long been used for the commercial production of natural colorants such as carotenoids and chlorophyll. Due to the rising demand for carotenoids and other natural products from microalgae, strategies to increase production efficiency are urgently needed. The production of microalgal biorefineries has been limited to countries with moderate climates. For countries with cooler climates and less daylight, methodologies for the efficient production of microalgal biorefineries need to be investigated. Algal strains that can be safely consumed as whole cells are also attractive alternatives for developing as carotenoid supplements, which can also contain other compounds with health benefits. Using such strains helps to eliminate the need for hazardous solvents for extraction and several other complicated steps. In this study, the mesophilic green alga Chlamydomonas reinhardtii was employed to study the effects of cold stress on cell physiology and the production of pigments and storage compounds. The results showed that temperatures between 10 and 20 °C induced carotenoid and chlorophyll accumulation in the wild-type strain of C. reinhardtii. Interestingly, the increased level of carotenoids suggested that they might play a crucial role in cold stress acclimation. A temperature of 15 °C resulted in the highest carotenoid and chlorophyll productivity. At this temperature, carotenoid and chlorophyll productivity was 2 times and 1.3 times higher than at 25 °C, respectively. Subjecting a mutant defective in lutein and zeaxanthin accumulation to cold stress revealed that these two carotenoids are not essential for cold stress survival. Therefore, cold temperature could be used as a strategy to induce and increase the productivity of pigments in C. reinhardtii.

scholarly journals Comparative analysis of the bioenergetics of human adenocarcinoma Caco-2 cell line and postoperative tissue samples from colorectal cancer patients

2018 ◽  
Vol 96 (6) ◽  
pp. 808-817 ◽  
Author(s):  
Lyudmila Ounpuu ◽  
Laura Truu ◽  
Igor Shevchuk ◽  
Vladimir Chekulayev ◽  
Aleksandr Klepinin ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cell Line ◽  
Respiratory Chain ◽  
Growth Conditions ◽  
Control Analysis ◽  
Respiratory Chain Complexes ◽  
Colon Tissue ◽  
Tissue Samples

The aim of this work was to explore the key bioenergetic properties for mitochondrial respiration in the widely-used Caco-2 cell line and in human colorectal cancer (HCC) postoperational tissue samples. Oxygraphy and metabolic control analysis (MCA) were applied to estimate the function of oxidative phosphorylation in cultured Caco-2 cells and HCC tissue samples. The mitochondria of Caco-2 cells and HCC tissues displayed larger functional activity of respiratory complex (C)II compared with CI, whereas in normal colon tissue an inverse pattern in the ratio of CI to CII activity was observed. MCA showed that the respiration in Caco-2 and HCC tissue cells is regulated by different parts of electron transport chain. In HCC tissues, this control is performed essentially at the level of respiratory chain complexes I–IV, whereas in Caco-2 cells at the level of CIV (cytochrome c oxidase) and the ATP synthasome. The differences we found in the regulation of respiratory chain activity and glycose index could represent an adaptive response to distinct growth conditions; this highlights the importance of proper validation of results obtained from in-vitro models before their extrapolation to the more complex in-vivo systems.

scholarly journals Effects of milk diets containing beef tallow or coconut oil on the fatty acid metabolism of liver slices from preruminant calves

2000 ◽  
Vol 84 (3) ◽  
pp. 309-318 ◽  
Author(s):  
Benoît Graulet ◽  
Dominique Gruffat-Mouty ◽  
Denys Durand ◽  
Dominique Bauchart
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Beef Tallow ◽  
Neutral Lipids ◽  
Lipid Production ◽  
Coconut Oil ◽  
Acid Oxidation ◽  
Milk Diet ◽  
Liver Slices ◽  
Triacylglycerol Accumulation

Coconut oil (CO) induces a triacylglycerol infiltration in the hepatocytes of preruminant calves when given as the sole source of fat in the milk diet over a long-term period. Metabolic pathways potentially involved in this hepatic triacylglycerol accumulation were studied by in vitro methods on liver slices from preruminant Holstein × Friesian male calves fed a conventional milk diet containing CO (n 5) or beef tallow (BT, n 5) for 19 d. Liver slices were incubated for 12 h in the presence of 0·8 mM-[14C] oleate or -[14C] laurate added to the medium. Fatty acid oxidation was determined by measuring the production of CO2 (total oxidation) and acid-soluble products (partial oxidation). Production of CO2 was 1·7–3·6-fold lower (P 0·0490) and production of acid-soluble products tended to be lower (P = 0·0625) in liver slices of CO- than BT-fed calves. Fatty acid esterification as neutral lipids was 2·6– to 3·1–fold higher (P = 0·0088) in liver slices prepared from calves fed the CO diet compared with calves fed the BT diet. By contrast with what occurs in the liver of rats fed CO, the increase in neutral lipid production did not stimulate VLDL secretion by the hepatocytes of calves fed with CO, leading to a triacylglycerol accumulation in the cytosol. It could be explained by the reduction of fatty acid oxidation favouring esterification in the form of triacylglycerols, in association with a limited availability of triacylglycerols and/or apolipoprotein B for VLDL packaging and subsequent secretion.

scholarly journals Engineering cytoplasmic acetyl-CoA synthesis decouples lipid production from nitrogen starvation in the oleaginous yeast Rhodosporidium azoricum

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Silvia Donzella ◽  
Daniela Cucchetti ◽  
Claudia Capusoni ◽  
Aurora Rizzi ◽  
Silvia Galafassi ◽  
...  
Keyword(s):  
Lipid Content ◽  
Nitrogen Starvation ◽  
Neutral Lipids ◽  
Lipid Production ◽  
Industrial Process ◽  
Wild Type ◽  
Lipid Concentration ◽  
Atp Citrate Lyase ◽  
Acetyl Coa ◽  
Engineered Strain

Abstract Background Oleaginous yeasts are able to accumulate very high levels of neutral lipids especially under condition of excess of carbon and nitrogen limitation (medium with high C/N ratio). This makes necessary the use of two-steps processes in order to achieve high level of biomass and lipid. To simplify the process, the decoupling of lipid synthesis from nitrogen starvation, by establishing a cytosolic acetyl-CoA formation pathway alternative to the one catalysed by ATP-citrate lyase, can be useful. Results In this work, we introduced a new cytoplasmic route for acetyl-CoA (AcCoA) formation in Rhodosporidium azoricum by overexpressing genes encoding for homologous phosphoketolase (Xfpk) and heterologous phosphotransacetylase (Pta). The engineered strain PTAPK4 exhibits higher lipid content and produces higher lipid concentration than the wild type strain when it was cultivated in media containing different C/N ratios. In a bioreactor process performed on glucose/xylose mixture, to simulate an industrial process for lipid production from lignocellulosic materials, we obtained an increase of 89% in final lipid concentration by the engineered strain in comparison to the wild type. This indicates that the transformed strain can produce higher cellular biomass with a high lipid content than the wild type. The transformed strain furthermore evidenced the advantage over the wild type in performing this process, being the lipid yields 0.13 and 0.05, respectively. Conclusion Our results show that the overexpression of homologous Xfpk and heterologous Pta activities in R. azoricum creates a new cytosolic AcCoA supply that decouples lipid production from nitrogen starvation. This metabolic modification allows improving lipid production in cultural conditions that can be suitable for the development of industrial bioprocesses using lignocellulosic hydrolysates.

Changes in the photosynthetic apparatus and lipid droplet formation in Chlamydomonas reinhardtii under iron deficiency

2018 ◽  
Vol 139 (1-3) ◽  
pp. 253-266 ◽  
Author(s):  
Elsinraju Devadasu ◽  
Dinesh Kumar Chinthapalli ◽  
Nisha Chouhan ◽  
Sai Kiran Madireddi ◽  
Girish Kumar Rasineni ◽  
...  
Keyword(s):  
Iron Deficiency ◽  
Chlamydomonas Reinhardtii ◽  
Lipid Droplet ◽  
Photosynthetic Apparatus ◽  
Droplet Formation ◽  
Lipid Droplet Formation

scholarly journals Combinatorial Metabolic Engineering in Saccharomyces cerevisiae for the Enhanced Production of the FPP-Derived Sesquiterpene Germacrene

2020 ◽  
Vol 7 (4) ◽  
pp. 135
Author(s):  
Jan Niklas Bröker ◽  
Boje Müller ◽  
Dirk Prüfer ◽  
Christian Schulze Gronover
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Metabolic Engineering ◽  
Metabolic Flux ◽  
Mevalonate Pathway ◽  
Plant Secondary Metabolites ◽  
Product Formation ◽  
Culture Conditions ◽  
Efficient Production ◽  
Enhanced Production ◽  
Engineering Strategy

Farnesyl diphosphate (FPP)-derived isoprenoids represent a diverse group of plant secondary metabolites with great economic potential. To enable their efficient production in the heterologous host Saccharomyces cerevisiae, we refined a metabolic engineering strategy using the CRISPR/Cas9 system with the aim of increasing the availability of FPP for downstream reactions. The strategy included the overexpression of mevalonate pathway (MVA) genes, the redirection of metabolic flux towards desired product formation and the knockout of genes responsible for competitive reactions. Following the optimisation of culture conditions, the availability of the improved FPP biosynthesis for downstream reactions was demonstrated by the expression of a germacrene synthase from dandelion. Subsequently, biosynthesis of significant amounts of germacrene-A was observed in the most productive strain compared to the wild type. Thus, the presented strategy is an excellent tool to increase FPP-derived isoprenoid biosynthesis in yeast.

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