Differential effects of nitrogen and sulfur deprivation on growth and biodiesel feedstock production of Chlamydomonas reinhardtii

Cakmak, T.
Angun P.
Demiray, Y.E.
Ozkan, A.D.
Elibol, Z.
Tekinay, T.
Source Title
Biotechnology and Bioengineering
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Electronic ISSN
1947 - 1957
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Volume Title

Biodiesel production from microalgae is a promising approach for energy production; however, high cost of its process limits the use of microalgal biodiesel. Increasing the levels of triacylglycerol (TAG) levels, which is used as a biodiesel feedstock, in microalgae has been achieved mainly by nitrogen starvation. In this study, we compared effects of sulfur (S) and nitrogen (N) starvation on TAG accumulation and related parameters in wild-type Chlamydomonas reinhardtii CC-124 mt(-) and CC-125 mt(+) strains. Cell division was interrupted, protein and chlorophyll levels rapidly declined while cell volume, total neutral lipid, carotenoid, and carbohydrate content increased in response to nutrient starvation. Cytosolic lipid droplets in microalgae under nutrient starvation were monitored by three-dimensional confocal laser imaging of live cells. Infrared spectroscopy results showed that relative TAG, oligosaccharide and polysaccharide levels increased rapidly in response to nutrient starvation, especially S starvation. Both strains exhibited similar levels of regulation responses under mineral deficiency, however, the degree of their responses were significantly different, which emphasizes the importance of mating type on the physiological response of algae. Neutral lipid, TAG, and carbohydrate levels reached their peak values following 4 days of N or S starvation. Therefore, 4 days of N or S starvation provides an excellent way of increasing TAG content. Although increase in these parameters was followed by a subsequent decline in N-starved strains after 4 days, this decline was not observed in S-starved ones, which shows that S starvation is a better way of increasing TAG production of C. reinhardtii than N starvation. © 2012 Wiley Periodicals, Inc.

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Book Title
Biodiesel, Chlamydomonas reinhardtii, Microalgae, Nitrogen starvation, Sulfur starvation, Triacylglycerol, Biodiesel feedstock, Biodiesel production, Carbohydrate content, Cell divisions, Cell volume, Chlamydomonas reinhardtii, Cytosolic, Differential effect, Energy productions, High costs, Laser imaging, Lipid droplets, Live cell, Micro-algae, Neutral lipid, Nitrogen starvation, Nutrient-starvation, Peak values, Physiological response, Process limits, Sulfur deprivation, Triacylglycerols, Wild types, Algae, Biodiesel, Carbohydrates, Cell proliferation, Chlorophyll, Feedstocks, Glycerol, Infrared spectroscopy, Microorganisms, Nitrogen, Nutrients, Sulfur, Physiological models, algal protein, amide, biodiesel, carbohydrate, carotenoid, chlorophyll, lipid, nitrogen, oligosaccharide, polysaccharide, starch, sulfur, triacylglycerol, algal cell culture, algal growth, article, biofuel production, cell division, cell volume, Chlamydomonas reinhardtii, confocal laser microscopy, controlled study, cytosol, infrared spectroscopy, nonhuman, nutrient limitation, three dimensional imaging, wild type, Biofuels, Carbohydrates, Chlamydomonas reinhardtii, Cytosol, Lipids, Nitrogen, Plant Proteins, Spectrum Analysis, Sulfur, Triglycerides, algae, Chlamydomonas reinhardtii
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