Induction of triacylglycerol production in Chlamydomonas reinhardtii: Comparative analysis of different element regimes

Abstract

In this study, impacts of different element absence (nitrogen, sulfur, phosphorus and magnesium) and supplementation (nitrogen and zinc) on element uptake and triacylglycerol production was followed in wild type Chlamydomonas reinhardtii CC-124 strain. Macro- and microelement composition of C. reinhardtii greatly differed under element regimes studied. In particular, heavy metal quotas of the microalgae increased strikingly under zinc supplementation. Growth was suppressed, cell biovolume, carbohydrate, total neutral lipid and triacylglycerol levels increased when microalgae were incubated under these element regimes. Most of the intracellular space was occupied by lipid bodies under all nutrient starvations, as observed by confocal microscopy and transmission electron micrographs. Results suggest that sulfur, magnesium and phosphorus deprivations are superior to nitrogen deprivation for the induction triacylglycerol production in C. reinhardtii. On the other hand, FAME profiles of the nitrogen, sulfur and phosphorus deprived cells were found to meet the requirements of international standards for biodiesel.

Growth of mono- and mixed cultures of Nannochloropsis salina and Phaeodactylum tricornutum on struvite as a nutrient source

“…For some algae species, especially fresh water variants, the presence of increased loadings of trace metals may be deleterious. In a previous study, the authors concluded that trace metals are a dominant factor in physiological changes in algal cells (Cakmak et al, 2014). Here we observed that the effective mean diameter of the algae cells was larger for both algae strains when cultivated in L1 versus crude struvite at stationary phase, but no significant size differences were observed between the L1 and purified struvite cultures, potentially resulting from the presence of additional trace metals in the crude material.…”

Assessment of a Novel Algal Strain Chlamydomonas debaryana NIREMACC03 for Mass Cultivation, Biofuels Production and Kinetic Studies

“…with 4 % CO 2 whereas Nannochloropsis salina shown 0.104 ± 0.0076 g L −1 day −1 with 2 % CO 2 . With evidence to literature [13,[22][23][24][25], nitrogen stress has phenomenal result in lipid enhancing. C. debaryana biomass from the early stationary phase and was transferred into complete nitrogen deficient (N (−) ) BBM medium and allowed to grow for further 10 days.…”

“…TAI-2 grown in modified BBM medium with 3 % CO 2 using 6-L glass columni-form flask photobioreactor [20] and Chlamydomonas reinhardtii grown with 6.8 ± 1.0 % CO 2 [21]. Likewise, Pegallapati and Nirmalakhandan [13] did their study on biomass production in 18 L internally illuminated photobioreactor (IIPBR) and achieved 0.401 ± 0.07 g L −1 day −1 from Scenedesmus sp. with 4 % CO 2 whereas Nannochloropsis salina shown 0.104 ± 0.0076 g L −1 day −1 with 2 % CO 2 .…”

“…High growth rate and autosediment on steady state made NIREMACC03 a model strain for mass cultivation study. Under stress conditions, most microalgae directs their metabolism to the yield of non-polar lipids and especially, triglycerides (TAG), and one of the most widely used stress conditions is nutrient starvation, which strongly induces TAG production of microalgae [13]. This hypothesis was validated using our model strain C. debaryana cultivating in nutritional stress and change in physicochemical property were studied.…”

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“…In the general sense, when a stress condition arises, microalgae tend to store photosynthetic energy in the form of lipids and carbohydrates at the expense of reduced growth rate (Juneja, Ceballos, & Murthy, 2013). Nitrogen limitation or starvation of microalgae has been employed as an effective strategy to induce production of lipids (Cakmak, Olmez, Cakmak, Menemen, & Tekinay, 2014), carbohydrates (Dean, Sigee, Estrada, & Pittman, 2010) and carotenoids (Markou & Nerantzis, 2013) along with a simultaneous reduction in total protein content. Miscellaneous impacts of nitrogen deficiency include a decrease in chlorophyll content, carbon dioxide fixation, and oxygen evolution (Peccia, Haznedaroglu, Gutierrez, & Zimmerman, 2013).Ammonium nutrition was reported to increase the amino-acid content of…”