12 Industrial Extraction of Microalgal Pigments
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Table 12.2
Summary (1st) of previous studies investigating astaxanthin extraction from microalgal biomass
Study
Species
Biomass
state
Pretreatment and
cell rupture
Extraction solvents and
conditions
Maximum yield/recovery at
optimum conditions
Key findings
Molino
et al.
(2018)
Haematococcus
pluvialis
Red cyst,
freeze-dried
Mixed with
diatomaceous earth,
bead milled
Pressurised solvent
extraction with acetone,
ethanol or
chloroform/methanol
(1:1), hexane
87 wt% of available
astaxanthin with acetone at
100 bar & 40 °C
Mechanical pretreatment
improved astaxanthin yield
by 3 orders of magnitude.
Astaxanthin was degraded
at high temperature
beyond 40 °C for acetone
and 67 °C for ethanol
Desai
et al.
(2016)
H. pluvialis
spray-dried Ionic liquid
permeabilisation at
25, 45, 55 or 65 °C.
Seven ionic liquids
from three different
classes
(imidazolium,
ammonium and
phosphonium) were
trialled
Two stages of ethyl
acetate extraction
>70 wt% of available
astaxanthin with biomass
pretreatment using
1-ethyl-3-methylimidazolium
dibutylphosphate (EMIM
DBP) at 45 °C and 40% w/w
in water
Ionic liquids did not
disrupt the cell wall;
instead, the liquids
dissolved part of the
mannan polysaccharide in
the cell wall,
perforating/permeabilising
the walls to form tiny
passages that enabled
subsequent organic
solvents to penetrate the
cells and extract
astaxanthin
(continued)