Bioprocess and Biosystems Engineering (2018) 41:457–465
Eﬀects of light-emitting diode (LED) with a mixture of wavelengths
on the growth and lipid content of microalgae
Chae Hun Ra
· Phunlap Sirisuk
· Jang‑Hyun Jung
· Gwi‑Taek Jeong
· Sung‑Koo Kim
Received: 15 September 2017 / Accepted: 12 December 2017 / Published online: 19 December 2017
© Springer-Verlag GmbH Germany, part of Springer Nature 2017
Integrations of two-phase culture for cell growth and lipid accumulation using mixed LED and green LED wavelengths
were evaluated with the microalgae, Phaeodactylum tricornutum, Isochrysis galbana, Nannochloropsis salina, and Nan-
nochloropsis oceanica. Among the single and mixed LED wavelengths, mixed LED produced higher biomass of the four
microalgae, reaching 1.03 g DCW/L I. galbana, followed by 0.95 g DCW/L P. tricornutum, 0.85 g DCW/L N. salina, and
0.62 g DCW/L N. oceanica than single LED or ﬂuorescent lights at day 10. Binary combination of blue and red LEDs could
produce the high biomass and photosynthetic pigments in the four microalgae. The highest lipid accumulation during second
phase with the exposure to green LED wavelengths was 56.0% for P. tricornutum, 55.2% for I. galbana, 53.0% for N. salina,
and 51.0% for N. oceanica. The major fatty acid in the four microalgae was palmitic acid (C16:0) accounting for 38.3–47.3%
(w/w) of the total fatty acid content.
Keywords Microalgae · Fatty acid · Mixed LED · Green LED · Two-phase culture
Microalgal biomass is used as a feedstock for food or feed
supplements, nutraceuticals, and cosmetics, and has been
considered as a promising feedstock for aquaculture .
Microalgae play a vital role in aquatic food chain and are
popularly used in rearing aquatic animals like mollusks,
shrimps, and ﬁshes at diﬀerent growth stages . In addi-
tion, microalgal photosynthesis has been recognized as one
of the most cost-eﬀective ways to solve global warning .
The four microalgae Phaeodactylum tricornutum, Isochry-
sis galbana, Nannochloropsis salina, and Nannochloropsis
oceanica have desirable merits to contribute to environmen-
tal and economic issues such as their carbon ﬁxation, high
biomass productivity, and lipid synthesis [4–6].
Photoautotrophic microalgae absorb light energy (pho-
tons) and convert it into chemical energy, such as in the
form of ATP and NADPH. These reactions occur in the
microalgal photosystems and the absorption of light energy
occurs via chlorophyll pigments and carotenoids . Thus,
the wavelength and intensity of light play key roles in the
process of photosynthesis for photoautotrophic microalgal
growth and also aﬀect lipid production by microalgae .
The wavelengths absorbed by microalgae diﬀer depending
on the species.
Chlorophylls and carotenoids are the two major classes
of photosynthetic pigments found in plants and algae. Chlo-
rophyll a (Chl a) is the primary molecule responsible for
photosynthesis, while chlorophyll b (Chl b) is an accessory
pigment, the level of which increases upon exposure to a
broad spectrum of light that transfers the energy to Chl a.
Carotenoids as photosynthetic pigments play a role of excess
energy disposal. The absorbance maxima of chlorophylls
and carotenoids are in the red and blue wavelength regions
of the light spectrum .
The use of speciﬁc narrow bands of light using light-
emitting diode (LED) is more economical than using ordi-
nary light sources with cost-eﬀective low-wattage irradi-
ance. Indeed, the light absorption ability of photosystem II
was improved by red light, while that of photosystem I was
Chae Hun Ra and Phunlap Sirisuk are co-ﬁrst authors (equal
* Sung-Koo Kim
Department of Biotechnology, Pukyong National University,
Busan 48513, South Korea
Amicogen, lnc, #1259 Dongburo, Jinsung, Jinju 36367,