Effects of temperature and nutrient regimes on biomass and lipid production

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Bioresource Technology 129 (2013) 439–449

Contents lists available at SciVerse ScienceDirect

Bioresource Technology
journal homepage: www.elsevier.com/locate/biortech

Effects of temperature and nutrient regimes on biomass and lipid production
by six oleaginous microalgae in batch culture employing a two-phase cultivation
strategy
Michael Y. Roleda ⇑,1, Stephen P. Slocombe 1, RaymondJ.G. Leakey, John G. Day, Elanor M. Bell,
Michele S. Stanley
Scottish Association for Marine Science, Scottish Marine Institute, Oban, Argyll PA37 1QA, Scotland, UK

highlights

graphical abstract

" Nutrient and temperature

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"

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interactively affect growth but no
additive effect on lipid accumulation
of oleaginous microalgae.
Growth rate and fatty acid content
werenegatively correlated.
Triacylglycerol accumulation was a
default response to environmental
stress.
Stress conditions led to reduced fatty
acid unsaturation.
Nutrient limitation was the most
critical factor affecting lipid
metabolism.

article

info

Article history:
Received 20 June 2012
Received in revised form 6 November 2012
Accepted 7 November 2012
Available online 19 November2012
Keywords:
Biofuel
Fatty acid
Growth
Microalgae
Stress physiology

abstract
Commercial success of algal-based biofuels depends on growth characteristics and lipid metabolism of
the production species. The oleaginous microalgae, Thalassiosira pseudonana, Odontella aurita, Nannochloropsis oculata, Isochrysis galbana, Chromulina ochromonoides, and Dunaliella tertiolecta, were cultivatedunder a matrix of two temperatures (10 and 20 °C) and two nutrient regimes (deplete and replete).
For all species, a strong negative correlation between growth rate and lipid content was observed. Multiple stressors have no additive effect on lipid accumulation. Total oil content (fatty acid methyl esters,
FAMEs, pg cellÀ1) was increased more by nutrient limitation than by temperature stress. Inresponse
to nutrient stress, N. oculata emerged as the most robust species with an increase in lipid accumulation
of up to three to four-fold compared to the accumulation under nutrient sufficient conditions. Although
stress conditions led to reduced fatty acid unsaturation in most taxa due to increased triacylglycerol
(TAG) production, a high proportion of eicosapentaenoic acid (EPA) wasmaintained in O. aurita.
Ó 2012 Elsevier Ltd. All rights reserved.

1. Introduction
Microalgae are particularly attractive as feedstock for the production of lipid-based biofuels since they are adapted to grow over
⇑ Corresponding author. Present address: Department of Botany, University of
Otago, P.O. Box 56, Dunedin 9054, New Zealand. Tel.: +64 3 479 9061; fax: +64 3
479 7583.
E-mailaddress: michael.roleda@otago.ac.nz (M.Y. Roleda).
1
These authors have equal contributions.
0960-8524/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.biortech.2012.11.043

a wide range of environmental conditions with, in many cases,
short doubling times (Mata et al., 2010). Furthermore, their survival
strategies are often underpinned by the presence ofdiverse and
unusual patterns of cellular lipids and their capacity to modify lipid
metabolism in response to changes in environmental conditions.
Both biomass production and lipid accumulation are limited by a
variety of factors, of which nutrients (e.g. Chen et al., 2011; Feng
et al., 2011; Mairet et al., 2011), temperature (Fuentes-Grünewald
et al., 2012; Li et al., 2011a) and irradiance(Hu et al., 2008 and

440

M.Y. Roleda et al. / Bioresource Technology 129 (2013) 439–449

references therein) play key roles. Under optimal algal growth conditions, fatty acids are synthesized primarily for esterification into
glycerol-based membrane lipids. Conversely, under an unfavorable
environment or stressful conditions for growth, many algae alter
their lipid biosynthetic...
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