Effects of nitrogen and phosphorous stress on the formation of high value LC-PUFAs in Porphyridium cruentum

Abstract

This study systematically examined the effect of nitrogen and phosphorous stress on the formation of linoleic acid (LA), arachidonic acid (ARA), and eicosapentaenoic acid (EPA) in Porphyridium cruentum gy-h56. P. cruentum was cultivated in six different media conferring different conditions of nitrogen (N) sufficiency/deprivation and phosphorous (P) sufficiency/limitation/deprivation. Over a 16-day cultivation process, the dry-weight content, proportion of total fatty acids (TFAs), and the concentration in the medium of linoleic acid (LA) were greatly improved by a maximum of 2.5-, 1.6-, and 1.1-fold, respectively, under conditions of N or P deprivation compared with N and P sufficiency. In contrast, levels of EPA or ARA were not enhanced under N or P stress conditions. Additionally, the results showed that N deprivation weakened the impact of P deficiency on the content and proportions of LA and EPA, while P deprivation enhanced the impact of N starvation on the content and proportions of LA and EPA. The conditions of N sufficiency and P deprivation (N+P-) were the optimal conditions for the production of LA, while the optimal conditions for EPA, ARA, and TFAs production were N sufficiency and P limitation (N+P-lim). This study suggests the potential application of combining N removal from saline wastewater with the production of LA, ARA, EPA, and biodiesel.

Evaluation of the effect of agitation speed on the growth and high‐value LC‐PUFA formation of Porphyridium cruentum based on basic rheological analysis

“…The fatty acids (FAs), apart from LA, ARA and EPA, were analyzed in accordance with the method described by Rodriguez-Ruiz et al 34 Lyophilized microalgae powder (≈20 mg) was collected for transesterification. The steps and operating conditions for transesterification were based on the method of Chu et al 35 The FAs apart from the three LC-PUFAs were measured by gas chromatography (Agilent 6890, Agilent Technologies, Palo Alto, CA, USA) according to Hu et al 36 The content and production of TFAs, or LA, ARA and EPA, were calculated based on Eqns (1) and (2).…”

Effects of Different Environmental Factors on the Growth and Bioactive Substance Accumulation of Porphyridium purpureum

“…The lipids in Porphyridium are stored mainly in the form of triacylglycerol (TAG), which is transesterified to produce biodiesel and to provide energy for metabolic processes [14]. And some long-chain fatty acids (LC-PUFAs) have high medical value, such as eicosapentaenoic acid (EPA, C20: 5) that reduces the risk of diabetes, brain disease, inflammation, arteriosclerosis, heart disease, and several cancers, and arachidonic acid (ARA, C20: 4), which also has basic functions in the treatment of cardiovascular disease, rheumatoid arthritis, and cancer [15].…”

Growth and Biochemical Composition of Porphyridium purpureum SCS-02 under Different Nitrogen Concentrations

“…Nitrogen limitation promotes the accumulation of storage lipids, but reduces the accumulation of membrane lipids [8]. However, contradictory results regarding the effect of low nitrogen concentration on EPA and ARA production have been reported in many of the previous studies [9,15,16]. These changes in B-PE, LC-PUFAs and EPS concentrations resulting from the different nitrogen concentrations provide to be a theoretical foundation for the customised production of these three compounds.…”

“…Several studies examining the effects of nitrogen on the accumulation of B-PE, LC-PUFAs and EPS in P . purpureum have been reported in the past 10 years [ 9 , 10 , 11 ]. B-PE is one of the most well-known pigment-protein complexes; limitation of nitrogen can significantly inhibit the synthesis of B-PE, while sufficiency of nitrogen can substantially enhance the synthesis of B-PE [ 12 ].…”

“…The results from del Pilar Sánchez-Saavedra et al (2018) showed that the high light intensity could significantly improve the content of carbohydrate, protein and B-PE content [ 17 ]. Hu et al (2018) showed that phosphate limitation was not conducive to the accumulation of PUFAs [ 9 ]. Soanen et al (2016) showed that the increase in light and temperature could enhance the secretion of EPS in Porphyridium marinum [ 18 ].…”