Seasonal Variation of Lipids and Fatty Acids of the Microalgae Nannochloropsis oculata Grown in Outdoor Large-Scale Photobioreactors

Abstract

While focus in oil-producing microalgae is normally on nutrient deficiency, we addressed the seasonal variations of lipid content and composition in large-scale cultivation. Lipid content, fatty acid profiles and mono-di-and triglycerides (MAGs, DAGs, and TAGs) were analyzed during May 2007-May 2009 in Nannochloropsis oculata grown outdoors in closed vertical flat panels photobioreactors. Total lipids (TL) ranged from 11% of dry weight (DW) in winter to 30% of DW in autumn. 50% of the variation in TL could be explained by light and temperature. As the highest lipid content was recorded during autumn indicating an optimal, non-linear, response to light and temperature we hypothesize that enhanced thylakoid stacking under reduced light conditions resulted in more structural lipids, concomitantly with the increase in glycerides due to released photo-oxidative stress. The relative amount of monounsaturated fatty acids (MUFA) increased during autumn. This suggested a synthesis, either of structural fatty acids as MUFA, or a relative increase of C16:1 incorporated into TAGs and DAGs. Our results emphasize the significant role of environmental conditions governing lipid content and OPEN ACCESSEnergies 2012, 5 1578 composition in microalgae that have to be considered for correct estimation of algal oil yields in biodiesel production.

The impact of oxygen exposure on long-chain alkyl diols and the long chain diol index (LDI) – a long-term incubation study

“…Long chain keto-ols were not detected and mid-chain hydroxy methyl alkanoates were only present in trace amounts. This lipid composition is in good agreement with previous studies of the lipids of Nannochloropsis species (Volkman et al, 1992(Volkman et al, , 1993Olofsson et al, 2012;Mitra et al, 2015;Balzano et al, 2017;Zhang and Volkman, 2017). Analysis of the sediment and sea water from the Dutch Wadden Sea used, did not show the presence of LCDs.…”

“…The occurrence of C 14 , C 16 and C 18 saturated fatty acids and the C 20:5 PUFA in Nannochloropsis oculata is consistent with earlier studies of the lipid composition of Nannochloropsis species (Volkman et al, 1993;Olofsson et al, 2012;Xiao et al, 2013;Mitra et al, 2015;Balzano et al, 2017). These lipids showed significant decreases in concentration when exposed to aerobic conditions during 271 days of incubation, to the point of non-detection in the case of the C 20:5 PUFA.…”

Bifunctional Adsorbent-Catalytic Nanoparticles for the Refining of Renewable Feedstocks

“…Microalgal oil feedstock is typically rich in FFAs, containing mainly saturated C 16 (50 wt %) and unsaturated C 16 fatty acids (30 wt %). 52,53 As mentioned above, in biodiesel production, a refinery process is required to selectively remove these FFAs and make the feedstock suitable for processing. Thus, the AP-Ni-MSN based sequestration catalysis could be well integrated into the production chain of biodiesel, as it would remove the acidic FFAs that neutralize the transesterification catalyst and selectively upgrade the FFAs to diesel-range alkanes (Scheme 3).…”

Optimizing light regimes on growth and lipid accumulation in Ankistrodesmus fusiformis H1 for biodiesel production

“…Numerous studies have reported the lipid content in microalgae (e.g., Nannochloropsis, Chlorella sp., Monoraphidium dybowskii) can accumulatively increase under higher light intensity (Wahidin et al, 2013;Gwak et al, 2014;He et al, 2015b), but it had seldom reported for Ankistrodesmus sp. The lipid in microalgae primarily constitute of polar structural lipids (such as phospholipids and glycolipids) together with storage neutral lipids especially TAG which is the most important component for biodiesel production (Olofsson et al, 2012). Besides, the fatty acid composition also affects the quality of biodiesel in microalgae.…”