Seasonal variation of lipids and fatty acids of the microalgae Nannochloropsis oculata grown in outdoor large-scale photobioreactors

• While focus in oil-producing microalgae is normally on nutrient deficiency, weaddressed the seasonal variations of lipid content and composition in large-scalecultivation. Lipid content, fatty acid profiles and mono- di- and triglycerides (MAGs,DAGs, and TAGs) were analyzed during May 2007–May 2009 in Nannochloropsis oculatagrown outdoors in closed vertical flat panels photobioreactors. Total lipids (TL) rangedfrom 11% of dry weight (DW) in winter to 30% of DW in autumn. 50% of the variation inTL could be explained by light and temperature. As the highest lipid content was recordedduring autumn indicating an optimal, non-linear, response to light and temperature wehypothesize that enhanced thylakoid stacking under reduced light conditions resulted inmore structural lipids, concomitantly with the increase in glycerides due to releasedphoto-oxidative stress. The relative amount of monounsaturated fatty acids (MUFA)increased during autumn. This suggested a synthesis, either of structural fatty acids asMUFA, or a relative increase of C16:1 incorporated into TAGs and DAGs. Our resultsemphasize the significant role of environmental conditions governing lipid content and composition in microalgae that have to be considered for correct estimation of algal oilyields in biodiesel production.

Ämnesord

NATURVETENSKAP  -- Biologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences (hsv//eng)

Nyckelord

microalgae

Nannochloropsis oculata

large-scale

seasonal variation

light

temperature

biofuels

biodiesel

lipids

fatty acids

Environmental technology

Miljöteknik

Biotechnology

Bioteknik

Aquatic Ecology

Akvatisk ekologi

Bioenergy Technology

Bioenergiteknik/Energi- och Miljöteknik

Publikations- och innehållstyp

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