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R-Phycoerythrin from red macroalgae : Strategies for extraction and potential application in Biotechnological area.

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Applied Biotechnology, Food Science and Policy 2003:1(1) xx–xx
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Introduction
Phycobiliproteins are the major photosynthetic pigments
found in rhodophyta (red algae), cyanobacteria (blue-green
algae) and in a class of flagellate unicellular eukaryotic algae
(cryptomonads) (Roman et al 2002). They are involved in
the light-harvesting (in the visible region from 450 nm to
650 nm) complementing other pigments such as
chlorophylls or carotenoïds. Phycobiliproteins compose
supramolecular aggregates called phycobilisomes, which
are located near photosystem II, one of two pigment
complexes involved in the photosynthesis mechanism. This
spatial arrangement allows a transfer of light energy to
chlorophyll for photosynthesis with greater than 90%
efficiency (Redlinger and Gantt 1982; Glazer 1984; Gantt
1990; Talarico 1996).
Phycobiliproteins were classified into three families
according to their absorption properties: phycoerythrins
(λ max = 565 nm), PE (red); phycocyanins (λ max =
620 nm), PC (blue); allophycocyanins (λ max = 650 nm),
AP (blue-green) (Rüdiger 1994). According to the original
source of phycobiliproteins a further differentiation was
adopted: C for cyanobacteria, R for rhodophyta and B for
bangiales (a particular family of red algae).
R-phycoerythrin (RPE) is a phycobiliprotein found in
most red algae. For example, it is present in Palmaria
palmata, which possesses a high protein level (up to 35%
of dry weight) (Morgan et al 1980; Fleurence 1999a).This
seaweed, widely known as dulse, is used in Europe as a sea
vegetable and as an ingredient in the food industry
(Indergaard and Minsas 1991). The pigment is composed
of open chain tetrapyrrolic (bilin) covalently linked to the
apoprotein (Figure 1). RPE is a protein with a relative mass
of 240
000. It comprises two major subunits (α, β) with Mr
of 20
000 and 21
000 respectively, and a minor subunit of
Mr 30
000 (γ) (Hilditch et al 1991; Galland Irmouli et al
2000). The molecular weight of the non denatured protein
structure suggests a (αβ)6γ polypeptide structure.
However, some structure variations were also described.
For instance, RPE contained in the red alga Gracilaria longa
possesses an apparent molecular weight of about 260
000
and is characterised by the presence of 4 subunits α, β, γ, γ’
with molecular weights of 19
000, 21
5000, 30
000 and
33
000 respectively (D’Agnolo et al 1994).
Because of its spectral properties, phycoerythrin is
widely used in biochemical techniques and clinical
Correspondence: Joël Fleurence, Laboratoire de Biologie Marine,
UPRES EA 2663, ISOMER, UFR Sciences et Techniques, 2 Rue de la
Houssinière, BP 92 208 44 322, Nantes cedex 3, France; tel
+33
251
125
660; fax +33 251 125 668; email Joel.Fleurence@isomer.univ-nantes.fr
R-phycoerythrin from red macroalgae:
strategies for extraction and potential
application in biotechnology
Joël Fleurence
Laboratoire de Biologie Marine, UFR Sciences et Techniques, Université de Nantes, Nantes, France
Abstract: R-phycoerythrin (RPE) is a red fluorescent pigment belonging to the phycobiliprotein family. It is a protein with an apparent
molecular weight of Mr 240
000 , and comprises two major subunits of Mr 20
000 and Mr 21
000 respectively, and a minor subunit of
Mr 30
000. The RPE absorption spectrum shows three peaks with a maximum of 565 nm. This paper briefly describes several procedures
for the extraction and purification of the protein. Most are classical methods and include the grinding of algae in buffer solutions and
purification by chromatography or preparative electrophoresis. A new approach, based on cell wall hydrolysis by enzymes such as
xylanases and/or cellulases, was developed to obtain the RPE protein without the crushing of raw material. The pigment obtained is
then purified in one step using preparative electrophoresis. This enzymatic extraction of RPE produces a non denatured pigment, and
this recently patented biotechnological approach can be performed on a large scale. Here, the pros and cons of different extraction
modes are discussed, and the main uses and potential applications of phycoerythrin in food and biotechnological sectors are presented.
Keywords: macroalgae, R-phycoerythrin, enzymatic extraction process, biotechnological applications
Applied Biotechnology, Food Science and Policy 2003:1(1)
2
Fleurence
diagnoses. It is especially used as a fluorescent label in
immunoassay like other phycobiliproteins (Kronick and
Grossman 1983; Kronick 1986). RPE obtained from
Corallina officinalis or from Porphyra tenera (Nori) is
marketed by companies that specialise in the purchase of
biochemical reagents. Generally, the price of this pigment
is between 180 and 250 US dollars/mg, making RPE a
molecule of high value when extracted from algae.
Extraction processes of
phycoerythrin
Classical processes
The phycobiliproteins, especially phycoerythrin (PE), can
be extracted by soaking the seaweeds in water for several
days (Siegelman and Kycia 1978). This method extracts
the proteins by osmotic shock (Fleurence and Guyader
1995). However, this type of extraction takes a long time
and a partial degradation of phycoerythrin by the proteases
is the main disadvantage of this method.
Currently, most procedures used for the extraction of
RPE are based on cell wall breakage. In Corallina officinalis,
the macroalga is ground in liquid nitrogen and the resulting
powder is homogenised in the sodium phosphate buffer
pH 7.1 (Hilditch et al 1991). The pigment is further purified
by successive chromatographies (gel filtration and anion
exchange techniques). The same procedure based on the
mechanical grinding of frozen seaweeds was applied to the
extraction of RPE from red algae such as Phyllophora
antartica (MacColl et al 1996) or P. palmata (Galland-
Irmouli et al 2000). For P. palmata, however, the RPE was
purified by preparative electrophoresis after seaweed
grinding.
Grinding in liquid nitrogen is used to facilitate the
destruction of the cell wall, which is the main obstacle to
accessing and extracting the algal proteins. However, this
approach is not totally efficient for cell wall degradation
and is also costly on an industrial scale.
Alternative extraction methods for RPE or seaweed
proteins were investigated, and enzymatic hydrolysis of the
cell wall was suggested as another way of accessing algal
protein (Amano and Noda 1990; Fleurence 1999b).
Enzymatic processes
The biochemical composition of the cell wall is different
according to seaweed species. In rhodophyta P. palmata
(dulse), the cell wall mainly comprises a matrix of
polysaccharides [β- (1,3) / (1,4) D-Xylans] including a little
proportion of cellulose (3% w/w) and probably proteins
(Deniaud et al forthcoming). Regarding this composition, a
new strategy for algal protein extraction based on the
degradation of the cell wall by specific enzymes was
elaborated. In this context, the action of xylanases and
cellulases alone or coupled was tested. Xylanases and
cellulases were obtained from Aspergillus aculeatus and
Trichoderma resei, respectively. The optimal effect on the
extraction of RPE was observed with the combined action
of xylanases and cellulases. These data contradict those
previously describing the combined action of xylanases
(Disporotrichum sp) and cellulases (Trichoderma viride)
Figure 1 Structure of R-Phycoerythrin chromophoric group.
Table 1 Effect of the use of xylanases and cellulases activities
on the R-phycoerythrin extraction recovery
Yield recovery
of RPE
(% expressed
Temperature % Cellulase % Xylanases in total protein
(C°) pH /Substrate /Substrate extracted)
20 6 3.5 3.5 8.21
30 5 2 2 3.97
30 5 5 5 2.50
30 7 2 2 7.45
30 7 5 2 6.82
30 7 5 5 10.01
40 6 3.5 3.5 4.02
40 6 3.5 0.5 8.05
50 7 5 5 2.67
60 6 3.5 3.5 2.21
Applied Biotechnology, Food Science and Policy 2003:1(1) 3
R-phycoerythrin from red macroalgae
on protein extraction from P. palmata (Fleurence et al 1995).
However, the different biological source of xylanases could
explain this contradiction.
The better yield in phycoerythrin recovery (10% of RPE/
total protein extracted) was obtained with xylanases and
cellulases combined action at 30
°C at pH 7 over 4 hours
(Table 1). The ratios xylanases/algae and cellulases/algae
for an optimal extraction were 5% (w/w) (Table 1). On the
other hand, higher incubation temperatures (≥40
°C) or
lower pH (6≤ pH) led to a large decrease in the RPE recovery
yield (
–
70%) (Table 1). The RPE obtained after the
application of enzymatic processes was further purified
according to a standard protocol based on the use of
preparative electrophoresis (Galland-Irmouli et al 2000).
The amount of RPE extracted by enzymatic hydrolysis of
cell wall can reach 4 mg/g of dry alga. This is higher than
those generally recorded from procedures that grind
seaweeds (Table 2). The phycoerythrin obtained by this
Table 2 R-phycoerythrin (RPE) recovery yield comparison
according to the extraction and purification methods
Extraction and RPE
purification methods (mg/g of alga dry weight)
Grinding of frozen algae 0.40 (small scale purification)
Chromatography techniques 0.6 (large scale purification)
(Hilditch et al 1991)
Grinding of frozen algae 0.45
Preparative electophoresis
(Galland Irmouli et al 2000)
Cell wall enzymatic hydrolysis 4
Preparative electrophoresis
(Fleurence et al 2002)
94
67
43
30
20
kDa
R-phycoerythrin
Figure 2 Purity evaluation by SDS PAGE of R-phycoerythrin obtained by
enzymatic process and purified by preparative electrophoresis. (Experimental
conditions: I= 30 mA, time= 1h, stacking gel: 4
% acrylamide, separating gel: 12
%
(w/v), determination of RPE subunits: fluorescence emission and molecular
weight determination in SDS PAGE.)
-0,2
-0,15
-0,1
-0,05
0
0,05
450 460 470 480 490 500 510 520 530 540 550 560 570 580 590 600 610 620 630 640 650
nm
Absorbance
Figure 3 Spectrum of R-phycoerythrin obtained by extraction enzymatic process and purified by preparative electrophoresis.
simple protocol is pure (Figure 2) and shows the main
spectral characteristics (λ max = 565 nm, a peak at 499 nm
and a shoulder at 545 nm) of the non denatured pigment
(Figure 3).
Therefore, enzymatic process is not denaturant for the
pigment and it obtains a better yield in the recovery of RPE.
An international patent request (Fleurence et al 2002)
regarding the use of this biotechnical approach to improve
the extraction of P. palmata proteins and the nutritional
value, which is estimated by the in vitro digestibility method
(Savoie and Gauthier 1986), has been registered.
Applied Biotechnology, Food Science and Policy 2003:1(1)
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Fleurence
In addition, the size of proteins extracted is different
according to the activities of enzymes used in cell wall
degradation. For instance, the action of β glucanase (from
Aspergillus niger) on P. palmata allows extraction of
proteins showing a large distribution of molecular weights
(10 kDa <MW < 100 kDa) (Figure 4a). This is not the case
with the combined action of xylanases and cellulases for
which extraction of proteins possessing molecular weights
distributing between 90 and 30 kDa was observed (Figure
4b). Therefore, the enzymatic treatment of P. palmata algae
appears as a flexible method that allows the extraction of
proteins with different molecular sizes.
0
10
20
30
40
50
60
70
80
90
100
P1 P2 P3 P4 P5 P6 P7 P8 P9 P10 P11 P12 P13 P14 P15 P16 P17
Proteins extracted
Molecular weight (kDa)
Figure 4a Molecular weight ranges of Palmaria palmata proteins extracted by the enzymatic maceration (β-glucanases action). (Experimental conditions:
temperature: 40 °C incubation time: 6 h, determination of molecular weights: SDS PAGE.)
0
10
20
30
40
50
60
70
80
90
P1 P2 P3 P4 P5 P6 P7
Proteins extracted
Molecular weight (kDa)
Figure 4b Molecular weight ranges of Palmaria palmata proteins extracted by the enzymatic maceration (xylanase and cellulase combined action). (Experimental
conditions: temperature: 40 °C incubation time: 6 h, determination of molecular weights: SDS PAGE.)
Applied Biotechnology, Food Science and Policy 2003:1(1) 5
R-phycoerythrin from red macroalgae
Present and potential applications
of R-phycoerythrin
R-phycoerythrin is a fluorescent pigment that shows thermal
stability up to 60
°C (D’Agnolo et al 1993; Galland-Irmouli
et al 2000). RPE obtained from P. palmata is stable between
pH 3.5 and 9.5. These conditions are favourable for using
phycoerythrin as a colourant in the elaboration of cosmetic
or food products. However, the economic cost associated
with the extraction of RPE by classical means is a strong
deterrent for this type of industrial application. Conversely,
the use of enzymatic maceration could decrease the cost of
extraction especially if commercial enzymes are employed.
This is possible for some enzymatic activities previously
cited, such as the xylanases (shearzyme) or cellulases
(celluclast), which are commercially available and can be
purchased from Novo. Due to a lack of economic evaluation
for enzymatic extractive procedure used on a large scale, it
is as yet unknown if this new methodology could be cheaper
than the classical methods.
The original spectral properties and especially
fluorescence emission are the main advantages for a
biotechnical use of this algal pigment. Phycoerythrin
possesses an exceptionally high molar absorption coefficient
(near 2.4
×
106 M–1cm–1) and a quantum yield near 0.8, giving
the molecule a high sensitivity. PE emits in the orange-red
(fluorescence emission maxima = 580 nm), a spectral zone
where background fluorescence is exceptionally low. In
addition, RPE displays very intense fluorescence more than
20 times larger than those recorded for a molecular probe
such as fluorescein. Moreover, phycoerythrin shows optical
properties (eg lack of fluorescence background) appropriate
for use in molecular imaging 3-D technique (Chen et al
1997).
For these reasons, phycoerythrin conjugates, such as
antibody complex protein A-phycoerythrin and avidin-
phycoerythrin complexes, and can be used as a fluorescent
probe in flow cytometry, microscopy or immunoassay. The
use of RPE as a probe to evaluate the proximity or the
interaction between two molecules by fluorescence
resonance energy transfer (FRET) (Ha et al 1996) is also a
new perspective for the application of this algal pigment
(Galland-Irmouli et al 2000).
RPE subunits carry chromophoric groups and are
characterised by a deep rose colour. This property coupled
with the low molecular weight of subunits (Mr 20
000) is
an opportunity for using RPE as an internal marker in
electrophoretic techniques (non denaturant electrophoresis,
SDS-PAGE, isoelectrofocusing) (Araoz et al 1998) and size-
gel exclusion chromatography.
The utilisation of RPE for these biological properties
could also be another way to increase the valorisation
opportunities of this algal pigment. However, few studies
about the biological activities of this pigment are available,
presenting an opening for future research.
Currently, two main types of activities are linked to RPE:
anti parasitic and anti-tumour activities. Notably, RPE was
described as a defensive substance contained in the ink of
the marine mollusc Aplysia californica (Coelho et al 1998).
In this example, the pigment is provided by the red seaweeds
constituting the diet of the marine snail, and is further
modified by the animal digestion process.
Recently, anti-cancer activity was recorded for the RPE
and these three subunits α, β, γ (Bei et al 2002). The
experimentations were performed on cellular models (mouse
tumour cells, human liver carcinoma cells). The occlusion
of tumour blood vessels with the induction of cell
programmed death (apoptosis) appears to be the main
mechanism of RPE subunits. In addition, the natural
fluorescence of pigment subunits appears useful to follow
the pigment internalisation in the tumour cells.
Conclusion
R-phycoerythrin is an original pigment showing spectral
and biological properties of interest for industrial
application. The development of new extraction methods
such as enzymatic processes could decrease the economic
cost of obtaining RPE. Moreover, application of cell wall
enzymatic hydrolysis to improve protein extraction is also
applicable to other algae, and was successfully tested on
green seaweeds belonging to Ulva genus (Fleurence et al
1995). For these algae, enzymatic extractive process based
on application of cellulase, hemicellulase and β glucanase
mixture gave protein recovery yields comparable (18%–
22% expressed according to the total proteins) to those
recorded for efficient but denaturing chemical methods (eg
extraction with strong alkalis).
These previous works also demonstrated that each
process had to be adapted according to the chemical nature
of the cell wall. At present, lack of knowledge on cell wall
structure and sometimes the poor availability of some
enzymes appear to be the main restrictions to using this
biotechnical approach.
Nevertheless, cell wall enzymatic hydrolysis remains a
promising method for the extraction of proteins with high
Applied Biotechnology, Food Science and Policy 2003:1(1)
6
Fleurence
value, in non denaturant conditions. It could, for instance,
be tested for the extraction of particular phycoerythrins such
as the R-phycoerythrin IV found in Antarctic seaweeds or
B-phycoerythrin which is specific to the bangiale family
(eg Porphyra sp or Porhyridium sp).
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... These phycobiliproteins are composed of two different subunits, α and β. Only PE possesses another γ subunit in its central cavity, which allows a higher structural stability [18,[23][24][25]. R-PE is the major phycobiliprotein in red seaweeds and is responsible for their coloration [18,26]. ...
... It can be used as a pink colorant, particularly in the food industry, and as fluorescent probe in several technologies such as flow cytometry, fluorescent immunoassays or immunophenotyping [14,18,27,28]. R-PE was also characterized by several bioactivities such as antitumoral, anti-ageing, anti-inflammatory, antioxidant, antidiabetic, antiparasitic, immunosuppressive and antihypertensive ones [9,[16][17][18]22,24,26]. It also has potential in application in solar cells [27]. ...
... R-PE potential in nanotechnologies is also highlighted by a study exhibiting the great enhancement of its electrical conductivity with an association of Ag0 nanoparticles in the R-PE channel [29]. The price of R-PE generally varies between USD 180 and USD 250/mg and it depends principally on the R-PE purity [24]. ...
Quantification of Xylanolytic and Cellulolytic Activities of Fungal Strains Isolated from Palmaria palmata to Enhance R-Phycoerythrin Extraction of Palmaria palmata: From Seaweed to Seaweed
Article
Full-text available
  • Jul 2023
  • MAR DRUGS
R-phycoerythrin (R-PE) can be enzymatically extracted from red seaweeds such as Palmaria palmata. This pigment has numerous applications and is notably known as an antioxidant, antitumoral or anti-inflammatory agent. Enzymes secreted by P. palmata associated fungal strains were assumed to be efficient and adapted for R-PE extraction from this macroalga. The aim of the present study was to quantify both xylanolytic and cellulolytic activities of enzymatic extracts obtained from six Palmaria palmata derived fungal strains. Degradation of P. palmata biomass by fungal enzymatic extracts was also investigated, focused on soluble protein and R-PE extraction. Enzymatic extracts were obtained by solid state fermentation. Macroalgal degradation abilities were evaluated by measuring reducing sugar release using DNS assays. Soluble proteins and R-PE recovery yields were evaluated through bicinchoninic acid and spectrophotometric assays, respectively. Various enzymatic activities were obtained according to fungal isolates up to 978 U/mL for xylanase and 50 U/mL for cellulase. Enzymatic extract allowed high degrading abilities, with four of the six fungal strains assessed exhibiting at least equal results as the commercial enzymes for the reducing sugar release. Similarly, all six strains allowed the same soluble protein extraction yield and four of them led to an improvement of R-PE extraction. R-PE extraction from P. palamata using marine fungal enzymes appeared particularly promising. To the best of our knowledge, this study is the first on the use of enzymes of P. palmata associated fungi in the degradation of its own biomass for biomolecules recovery.
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... Therefore, all PBP are tasked with (1) capturing incident light, and (2) participating in the energy transfer chain. This energy transfer is unidirectional, highly efficient (greater than 90%) [28], and allows red seaweeds to harvest a much wider range of light wavelengths than the other groups of seaweeds [17] and thus, optimize their photosynthetic efficiency. PBP are considered accessory pigments of chlorophyll, and are key components of the photosynthetic light-harvesting complexes of red seaweeds [17] (and also Cyanobacteria, Cryptophyta, and Glaucophyta) [4]. ...
... Therefore, all PBP are tasked with (1) capturing incident light, and (2) participating in the energy transfer chain. This energy transfer is unidirectional, highly efficient (greater than 90%) [28], and allows red seaweeds to harvest a much wider range of light wavelengths than the other groups of seaweeds [17] and thus, optimize their photosynthetic efficiency. In fact, PBP are essential in guaranteeing the growth and adaptation of red algae, by optimizing their light-harvesting abilities in the deeper layers of the water column, where only the blue-green spectrum of the incident light prevails [4]. ...
... PBPs have noteworthy spectroscopic properties, such as high absorption coefficient, high excitation and emission spectra, high quantum yield, low interference, high quenching stability, and water solubility [4,31]. Therefore, they have been widely considered in several Phycology 2022, 2 5 and well documented applications, namely, in biomedical research, clinical diagnostics, therapeutic science, and cosmeceutical and pharmaceutical industries [1,28,32,33]. Namely, these pigments have been widely applied as fluorescent probes in flow cytometry, immunofluorescence microscopy [34], immunomodulation [35], and as photosynthesizers in cancer therapy [36]. ...
Red Seaweed Pigments from a Biotechnological Perspective
Article
Full-text available
  • Dec 2021
Algae taxa are notably diverse regarding pigment diversity and composition, red seaweeds (Rhodophyta) being a valuable source of phycobiliproteins (phycoerythrins, phycocyanin, and allophycocyanin), carotenes (carotenoids and xanthophylls), and chlorophyll a. These pigments have a considerable biotechnological potential, which has been translated into several registered patents and commercial applications. However, challenges remain regarding the optimization and subsequent scale-up of extraction and purification methodologies, especially when considering the quality and quantity needs, from an industrial and commercial point of view. This review aims to provide the state-of-the-art information on each of the aforementioned groups of pigments that can be found within Rhodophyta. An outline of the chemical biodiversity within pigment groups, current extraction and purification methodologies and challenges, and an overview of commercially available products and registered patents, will be provided. Thus, the current biotechnological applications of red seaweeds pigments will be highlighted, from a sustainable and economical perspective, as well as their integration in the Blue Economy
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... Red seaweeds are rich in phycoerythrin and carotenoids and also have a small degree of phycocyanin and chlorophyll a. Altogether, these pigmented metabolites provide these algae their unique red colors, hues and variations and, hence, their own place within the phylum Rhodophyta. These natural pigments, regardless of their source (as none is exclusively found in red macroalgae), have been widely studied recently, having a range of well-documented applications in biomedical research, therapeutics, clinical diagnosis and cosmeceutical/pharmaceutical industries, as well as application in food as both a coloring agent [84][85][86][87][88][89][90][91] and nutritional booster [92,93], and effectiveness as an antioxidant agent [94][95][96][97][98], among other bioactivities [34,95,[99][100][101]. ...
... These qualities render PBP suitable for applications in flow cytometry, immunofluorescence microscopy [104] and cancer therapy [105]. As such, these natural pigments have proven their usefulness in not only the cosmeceutical and pharmaceutic industries, as mentioned earlier (where they shine as bioactive agents), but also in biomedical research, clinical diagnostics and therapeutics [84][85][86]106]. ...
Primary Composition and Pigments of 11 Red Seaweed Species from the Center of Portugal
Article
Full-text available
  • Aug 2022
Macroalgae have been regarded as a natural food source since ancient times, their nutritional value being not only proven by recent studies, but also triggering further in-depth research efforts on the matter. The present study aims to provide an insight into the nutritional potential of selected red seaweed species collected in central Portugal by specifically comparing the moist yield and ash content, crude protein, total lipids, carbohydrates and pigment content between species and, ultimately, finding out if there are differences between taxa. The results obtained highlighted the most nutritionally appealing species, namely, Plocamium cartilagineum with respect to protein content (23.18% dw) and Sphaerocococcus coronopifolius with respect to carbohydrate content (40.23% dw), while none of the species studied showed a lipid content higher than 1.80% dw. Regarding pigment content, the highest concentrations of phycoerythrin, carotenoid and chlorophyll a were obtained, respectively, from P. cartilagineum (0.09 mg.mL−1), Porphyra umbilicalis (1.88 µg.g−1 fw) and Jania rubens (38.41 µg.mL−1). We concluded that there are significant differences between the species studied regarding their nutritional profile, with a marked difference between Corallinales and all other species not belonging to this order; regarding pigment content, this variation between orders was not observed. Nevertheless, all the studied species may act as promising complements in a human healthy diet.
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... Phycocyanin is the major phycobiliprotein, followed by phycoerythrin and allophycocyanin that were found in blue-green algae [5,6]. On the other hand, phycoerythrin is the dominant phycobiliprotein in most of the red algae, Rhodophyceae [7]. Besides, a few species of cryptophytes contain phycobiliproteins, and each cryptophyte usually has only one type of phycobiliproteins [8]. ...
... The fifth cluster ( Figure 6, in purple) focused on the phycobiliprotein applications especially as the fluorescent dye. As summarized in Section 3 (overview of previous phycobiliprotein research), phycobiliproteins have been widely utilized as highly valuable compounds or natural products in various industries ( Figure 9) [7,31,44,45,52]. Figure 11. The biosynthesis pathway of phycobiliproteins (adapted from [85,86]). ...
Uncovering Research Trends of Phycobiliproteins Using Bibliometric Approach
Article
Full-text available
  • Nov 2021
Phycobiliproteins are gaining popularity as long-term, high-value natural products which can be alternatives to synthetic products. This study analyzed research trends of phycobiliproteins from 1909 to 2020 using a bibliometric approach based on the Scopus database. The current findings showed that phycobiliprotein is a burgeoning field in terms of publications outputs with “biochemistry, genetics, and molecular biology” as the most related and focused subject. The Journal of Applied Phycology was the most productive journal in publishing articles on phycobiliproteins. Although the United States of America (U.S.A.) contributed the most publications on phycobiliproteins, the Chinese Academy of Sciences (China) is the institution with the largest number of publications. The most productive author on phycobiliproteins was Glazer, Alexander N. (U.S.A.). The U.S.A. and Germany were at the forefront of international collaboration in this field. According to the keyword analysis, the most explored theme was the optimization of microalgae culture parameters and phycobiliproteins extraction methods. The bioactivity properties and extraction of phycobiliproteins were identified as future research priorities. Synechococcus and Arthrospira were the most cited genera. This study serves as an initial step in fortifying the phycobiliproteins market, which is expected to exponentially expand in the future. Moreover, further research and global collaboration are necessary to commercialize phycobiliproteins and increase the consumer acceptability of the pigments and their products.
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... Lectin has shown great promise as an anti-HIV and anti-cancer drug but has yet to be commercially extracted and produced [68]. Phycobiliproteins are photosynthetic pigments found in red algae, used in the biomedical field as fluorescent markers [69]. R-phycoerythrin is the most common phycobiliprotein on the market and has a selling value of USD 180-250 M valuation per kilogram (Table 1). ...
Recent Advances in Seaweed Biorefineries and Assessment of Their Potential for Carbon Capture and Storage
Article
Full-text available
  • Sep 2023
Seaweeds are among the most important biomass feedstocks for the production of third-generation biofuels. They are also efficient in carbon sequestration during growth and produce a variety of high-value chemicals. Given these characteristics together with the relatively high carbohydrate content, seaweeds have been discussed as an ideal means for CO2 capture and biofuel production. Though third-generation biofuels have emerged as some of the best alternatives to fossil fuels, there is currently no large-scale production or mainstream use of such liquid fuels due to the many technical challenges and high production costs. The present study describes the concept of coastal marine biorefineries as the most cost-effective and sustainable approach for biofuel production from seaweeds, as well as atmospheric carbon capture and storage (CCS). The suggested refinery system makes use of marine resources, namely seawater, seaweed, and marine microorganisms. Firstly, extensive screening of the current literature was performed to determine which technologies would enable the emergence of such a novel biorefinery system and its merits over conventional refineries. Secondly, the study investigates various scenarios assessing the potential of seaweeds as a means of carbon sequestration. We demonstrate that the removal of 100 Gigatons of excess CO 2 using seaweed farms can be achieved in around 4 months to less than 12 years depending on the area under cultivation and the seaweed species. The total bioethanol that could be generated from the harvested biomass is around 8 trillion litres. In addition, high-value chemicals (HVC) that could potentially be recovered from the process represent a considerable opportunity with multi-billion-dollar commercial value. Overall, coastal marine biorefineries have strong potential for a sustainable green economy and represent a rapid approach to climate change mitigation.
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... Lectin has shown great promise as an anti-HIV and anti-cancer drug but has yet to be commercially extracted and produced [70]. Phycobiliproteins are photosynthetic pigments found in red algae, used in the biomedical field as fluorescent markers [71]. R-phycoerythrin is the most common phycobiliprotein on the market and has a selling value of 180-250 M USD valuation per kilogram (Table 1). ...
Recent Advances in Seaweed Biorefineries and Assessment of Their Potential for Carbon Capture and Storage
Preprint
Full-text available
  • Jul 2023
: Seaweeds are among the most important biomass feedstocks for the production of third generation biofuels. They are also efficient in carbon sequestration during growth, and produce a variety of high value chemicals. Given these characteristics together with the relatively high carbohydrate content, seaweeds have been discussed as an ideal means for CO2 capture and biofuel production. Though third generation biofuels have emerged as some of the best alternatives to fossil fuels, there is currently no large-scale production or mainstream use of such liquid fuels due to the many technical challenges and high production costs. The present study describes the concept of coastal marine biorefineries as the most cost-effective and sustainable approach for biofuel production from sea-weeds as well as atmospheric carbon capture and storage (CCS). The suggested refinery system makes use of marine resources, namely seawater, seaweed, and marine microorganisms. Firstly, extensive screening of the current literature was performed to determine which technologies would enable the emergence of such a novel biorefinery system and its merits over conventional refineries. Secondly, the study investigates various scenarios assessing the potential of seaweeds as a means of carbon sequestration. We demonstrate that the removal of 100 Gigatons of excess CO2 using seaweed farms can be achieved in around 4 months to less than 12 years depending on the area under cultivation and the seaweed species. The total bioethanol that could be generated from the harvested biomass is around 8 trillion litres. In addition, high-value chemicals (HVC) that could potentially be recovered from the process represent a considerable op-portunity with multi-billion-dollar commercial value. Overall, coastal marine biorefineries have strong potential for a sustainable green economy and rep-resent a rapid approach for climate change mitigation.
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... This phycoerythrin (Figure I-13) gives a double peak of absorbance at 498 and 565 nm, and a shoulder at 540 nm with a fluorescence emission maximum at 575 nm (Munier et al., 2015). R-PE is a high value compound that costs around 300 euros/mg (Munier et al., 2013a) or 180-250 USD/mg (Fleurence, 2003;Mittal and Raghavarao, 2018) following the purity level. ...
Etude de l’extrusion couplée à l’hydrolyse enzymatique pour l’extraction des composés hydrosolubles de l’algue rouge ‘’Gracilaria gracilis’’
Thesis
  • Jul 2022
L'algue rouge G.gracilis présente une teneur élevée en polysaccharides, protéines et autres composés bioactifs. L'extraction assistée par enzymes est une méthode de bioraffinage alternative aux procédés chimiques et mécaniques. La déstabilisation des membranes par l'activité enzymatique est connue pour libérer les composés confinés et inaccessibles, permettant ainsi d’améliorer les rendements d’extraction par rapport á des conditions modérées. L’extraction par hydrolyse enzymatique (Batch) et l’extrusion enzymatique (EE), ont été étudiées pour la libération des composés hydrosolubles de G.gracilis, notamment les protéines, les sucres et les R-phycoérythrines. Les résultats en Batch ont montré que le cocktail d'enzymes (mélange de cellulase et protéase) fonctionnait mieux sur la biomasse lyophilisée alors qu’une seule enzyme fonctionne mieux sur la biomasse fraîche et les rendements étaient plus élevés avec celle-ci. En fonction de l’état de la biomasse, différentes enzymes peuvent être utilisées et cela impact les rendements d'extraction. En outre, les résultats de l’EE avec la biomasse fraîche sont prometteurs. Les facteurs étudiés (débit d’alimentation, concentration d’enzyme et vitesse de la vis) affectent la libération des composés hydrosolubles. Le débit d’alimentation et la concentration d’enzyme sont les paramètres ayant le plus d’impact. Les rendements de l’EE suivis d’une macération rapide sont plus élevés comme les rendements en Batch. Ces techniques sont prometteuses pour le bioraffinage algale.
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... Most protein fractions, visualized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), ranged between 6.5 and 116 kDa. In most studies on Rhodophyta proteins, distinct bands were observed around 15, 20, 40, and 56 kDa representing R-PE (Pimentel et al., 2020), which comprises three subunits of α, β, and γ, with approximate molecular weights of 20, 21, and 31 kDa, respectively (Fleurence, 2003). Rosni, Fisal, Azwan, Chye, and Matanjun (2015) compared protein extracts from two green, four brown, and nine red seaweeds, and found that, besides some common fractions, subunits with a molecular weight of less than 15 kDa can vary significantly among different seaweed species. ...
Red seaweed: A promising alternative protein source for global food sustainability
Article
  • Mar 2022
  • TRENDS FOOD SCI TECH
Background With the increase in world population, decreased farmland, and global climate changes, ensuring adequate food supply to maintain food security is of immediate attention. As a key macronutrient for human health, the supply of sufficient dietary protein is undoubted of concern. Animal proteins are good dietary protein sources, but their production incurs a high carbon footprint; this has driven the effort to seek alternative protein sources. Scope and approach This review aimed to elaborate on the scientific research progress in red seaweed proteins, including the nutrition, functionalities, methods of extraction, and to explore their prospects as an alternative protein source. Applications of red seaweed protein in food and nutraceutical industries, environmental impact, affordability, and related safety concerns were also discussed. Key findings and conclusions Red seaweeds have a comparable essential amino acid profile to ovalbumin, representing a sustainable alternative to terrestrial proteins. Pre-treatment and extraction methods are pivotal in modulating protein digestibility and functionalities; enzymatic extraction approaches appear to improve nutritional value and food functionalities. Red seaweed proteins have a wide range of applications in food based on their physicochemical properties, while their bioactivities can be tailored for nutraceutical purposes. The use of red seaweed proteins as functional food ingredients is emerging, with good potential in bioactive microencapsulation. Efforts are required to improve the seaweed cultivation process to a commercial scale and gain consumer acceptance in the western world. More research is also necessary to enhance seaweed protein extraction and improve their functionalities for food and nutraceutical applications.
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... However, thermal degradation of PE also occurs. Phycobiliprotein extraction should then be facilitated by keeping the extraction at lower temperatures (22 • C or lower) and with a smaller starting seaweed particle size, as normally done by grinding the seaweed in liquid nitrogen to ensure destruction of the cell walls [27,28]. Considering that the total protein content in the dry Chondrus crispus chips is around 16-18 wt% (Table S1), the analyzed phycoerythrin (2.3 ± 0.1 mg/g dry seaweed) only makes up a minor fraction (around 1 wt%) of the total protein content of the seaweed. ...
Mechanical Disintegration and Particle Size Sieving of Chondrus crispus (Irish Moss) Gametophytes and Their Effect on Carrageenan and Phycoerythrin Extraction
Article
Full-text available
  • Nov 2021
To better understand the migration properties of hybrid carrageenan from the seaweed tissue during carrageenan extraction, the effect of increasing the seaweed surface area by the mechanical disintegration of gametophyte Chondrus crispus chips was studied under various temperature and time extraction conditions. Dried Chondrus crispus seaweed chips were milled by a rotor beater mill and classified into eight different size fractions by sieving with varying mesh sizes from 50 to 2000 μm. During extraction at 22 °C, the red color of the filtrate increased significantly with the decreasing particle size of the fraction, correlating with the increasing phycoerythrin concentration (from 0.26 mg PE/g dry seaweed in the >2000 μm size fraction to 2.30 mg PE/g dry seaweed in the <50 μm size fraction). On the other hand, under the same extraction conditions, only a small increase in carrageenan precipitate was obtained with the decreasing size fractions (from no recovery in the >2000 μm size fraction to 2.1 ± 0.1 g/kg filtrate in the <50 μm size fraction). This yield was significantly lower than the ones from extractions at 45 °C (5.4 ± 0.1 g/kg) or at 90 °C (9.9 ± 2.1 g/kg) for the same particle size and time conditions. It could be concluded that hybrid carrageenan extraction is not surface area dependent, while phycoerythrin is. Therefore, it seems that phycoerythrin and carrageenan extraction follow different mechanisms. This creates potential for the selective extraction of each of those two compounds.
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Extraction of high-value compounds from marine biomass via ionic liquid-based techniques
Chapter
  • Jan 2022
Ionic liquids (ILs) have been suggested as promising media to separate and extract bioactive compounds from a broad range of natural feedstocks. The unique physicochemical and solubilization properties of ILs have also led to new developments in separation science and materials science in recent years. This review highlights recent accomplishments in extraction processes of diverse high-value compounds from different kinds of marine biomass such as fish and marine algae via the use of ILs. High-value products targeted in recent studies through ILs-based processes include lipids, small organic extractable compounds, proteins, etc. Industrial applications of ILs for extraction processes often employ combinations with traditional organic solvents. Achievements as well as challenges of ILs-based processes are reviewed in this chapter.
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Processing Of Defensive Pigment in Aplysia Californica : Acquisition, Modification And Mobilization Of The Red Algal Pigment R-Phycoerythrin By The Digestive Gland
Article
Full-text available
  • Feb 1998
  • J EXP BIOL
The marine snail Aplysia californica obtains its purple defensive ink exclusively from the accessory photosynthetic pigment r-phycoerythrin, which is found in the red seaweeds of its diet. The rhodoplast digestive cell, one of three types of cell lining the tubules of the digestive gland, appears to be the site of catabolism of red algal chloroplasts (rhodoplasts) since thylakoid membranes, including phycobilisome-sized membrane-associated particles, were found within the large digestive vacuoles of this cell. Immunogold localization showed that there was a statistically significant occurrence of the red algal phycobilisome pigment r-phycoerythrin within these rhodoplast digestive vacuoles, but not in other compartments of this cell type (endoplasmic reticulum, mitochondria, nucleus) or in other tissues (abdominal ganglion). Immunogold analysis also suggested that the rhodoplast vacuole is the site for additional modification of r-phycoerythrin, which makes it non-antigenic: the chromophore is either cleaved from its biliprotein or the biliprotein is otherwise modified. The hemolymph had spectrographic absorption maxima typical of the protein-free chromophore (phycoerythrobilin) and/or r-phycoerythrin, but only when the animal had been feeding on red algae. Rhodoplast digestive cells and their vacuoles were not induced by the type of food in the diet: snails fed green seaweed and animals fed lettuce had characteristic rhodoplast cells but without the large membranous inclusions (rhodoplasts) or phycobilisome-like granules found in animals fed red seaweed. Two additional cell types lining the tubules of the digestive gland were characterized ultrastructurally: (1) a club-shaped digestive cell filled with electron-dense material, and (2) a triangular ‘secretory’ cell devoid of storage material and calcium carbonate. The following model is consistent with our observations: red algal rhodoplasts are freed from algal cells in the foregut and then engulfed by rhodoplast digestive cells in the tubules of the digestive diverticula, where they are digested in membrane-bound vacuoles; r-phycoerythrin is released from phycobilisomes on the rhodoplast thylakoids and chemically modified before leaving the digestive vacuole and accumulating in the hemolymph; the pigment then circulates throughout the body and is concentrated in specialized cells and vesicles of the ink gland, where it is stored until secreted in response to certain predators.
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Proteins of protoplasts from red alga Porphyra yezoensis
Article
  • Jan 1990
To elucidate the properties of protein in red alga Prophyra yezoensis, protoplasts having lesser amount of polysaccharides were used as a starting material. Protoplasts were isolated from Por-phyra by pre-treatment with protease followed by wall digesting enzyme mixture consisting of abalone enzyme and Macerozyme R-l0. Proteins in protoplasts were then extracted with low (I=0.05) and high (I=0.5) ionic strength phosphate buffer (pH 7.5) and 0.1N sodium hydroxide, and analyzed for protein composition, SDS-polyacrylamide gel electrophoretic pattern, and amino acid composition. The average content of crude protein in protoplasts was 32.7%, the amount being 5% higher than that of the thallus. The major protein in the protoplasts was water-soluble protein and it amounts to 43.2% of total nitrogen. Salt-soluble protein was a minor fraction (3.1% of total nitrogen). Electrophoretic pattern of the protein fractions consisted of many bands, and that of the water-soluble protein fraction was closely similar to that of the corresponding fractions from the thallus. In contrast, the patterns of salt-soluble and alkali-soluble protein fractions were different between protoplasts and thallus. Amino acid composition, however, was similar in all protein fractions from both protoplasts and thallus. The proteins were rich in aspartic and glutamic acids, alanine and leucine, and poor in histidine and methionine.
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Review of chemical constituents of the red alga Palmaria palmata (dulse)
Article
  • Oct 1980
The data reported in the literature and recent analyses of the composition ofPalmaria palmata (Rhodymenia palmata) are compiled and discussed. The reported values have a relatively wide spread ranging from 73–89% moisture and, on a dry weight basis, 12–37% ash, 8–35% crude protein, 38–74% carbohydrate and 0.2–3.8% lipid. Some of the variation can be attributed to seasonal and nutritional conditions.P. palmata has potassium, chlorine and sodium as its major mineral constituents and, in comparison to terrestrial fruits and vegetables, is a good source of iron, magnesium, calcium and iodine. Vitamin A (as carotene) and, in the fresh plant, vitamin C, are present in appreciable amounts.P. palmata is potentially a high protein food source, and its protein quality rates well with vegetables of good nutritional value. The major polysaccharide is a ß-(l → 3) and ß-(l →4) linked xylan.P. palmata is a natural source of desmosterol.
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Interactions of the mix-linked β-(1,3)/β-(1,4)-D-xylans in the cell walls of Palmaria palmata (Rhodophyta)
Article
  • Feb 2003
  • J PHYCOL
Algal cell wall mechanical properties, crucial for biological functions and commercial applications, rely on interactions in macromolecular assemblies. In an effort to better understand the interactions of the matrix-phase β-(1,3)/(1,4)-d-xylan in the edible seaweed Palmaria palmata ((L.) O. Kuntze, Rhodophyta, Palmariales), sequential extractions by saline, alkaline, and chaotropic solutions were done. The chemical composition and structure and the physicochemical properties of the isolated xylan revealed that it was partly acidic, probably due to the presence of sulfate (up to 5%) and phosphate groups (up to 4%). Although such acidity suggested ionic interactions of xylan in the cell walls, the high yields of polysaccharide extracted by alkali and particularly by 8 M urea and 4.5 M guanidium thiocyanate demonstrated that it was mainly hydrogen bonded in the cell wall. H-bonds did not appear to be related to the mean proportions of β-(1,3) and β-(1,4)-d-xylose linkages because these did not differ between extracts of increasing alkalinity. However, the decreasing molar weight and intrinsic viscosity of extracts obtained by alkaline solution containing a reducing agent used to prevent polysaccharide degradation suggested the presence of an alkali-labile component in the xylan. These results are discussed with regard to the role of potential wall proteins as a means of control of these interactions.
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Phycobiliproteins and phycobilisomes in red algae: Adaptive responses to light
Article
  • Jan 1996
The adaptive responses of the photosynthelic apparatus of Rhodophyta to light quality and quantity, relative to their light-harvesting complexes, the phycobilisomes (PBS) and the PBS components, particularly R-phycoerythrin, are reviewed in relation to pigment content, photosynthetic performance, algal growth and morphology in both the short and long term. Information available on fine structure, pigment composition and adaptive response of hemidiscoidal phycobilisomes from Cyanophyta is presented and critically compared to that, still scarce, regarding the hemiellipsoidal phycobilisomes, which are widespread in Florideophyceae containing R-phycoerythrin. Molecular characteristics and spectroscopic variations of this pigment are considered in relation to different light conditions. Particular emphasis is placed on the presence of well structured phycobilisomes during maximum photosynthetic activity, which appears to be not so strictly related to pigment content, and on the spectral changes of R-phycoerythrin, as a response to different wavelengths and irradiances of light.
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The enzymatic degradation of algal cell walls: A useful approach for improving protein accessibility?
Article
  • Jun 1999
With protein contents higher than 20% (dry weight), some red or green seaweeds are potential sources of commercially useful plant proteins. However, the presence of anionic or neutral polysaccharides in large quantities in the cell wall strongly hinders the solubilization of proteins during the application of classical extraction procedures. A present this limits the study and industrial use of seaweed proteins. This short paper is a discussion about the use of enzymes degrading the cell wall polysaccharides as an alternative method to improve the extraction and the solubilization of algal proteins.
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Comparison of different extractive procedures for proteins from the edible seaweeds Ulva rigida and Ulva rotundata
Article
  • Dec 1995
Proteins have been extracted from the edible seaweeds Ulva rigida Agardh and Ulva rotundata Bliding using classical or enzymatic procedures. The protocols using NaOH under reductive conditions or a two-phase system (PEG/K2CO3) produced the best protein yields. The cleavage or the limitation of the linkages between proteins and polysaccharides caused by these experimental conditions probably explains the efficiency of these protocols. In SDS PAGE, the protein fraction obtained after NaOH extraction from U. rotundata is characterised by the presence of three major bands with apparent molecular weights of 45 600, 31 800 and 18 600. The protein fraction from U. rigida presents two specific bands with apparent molecular weights of about 27 000 and 12 000. These fractions are mainly rich in aspartic and glutamic acids, alanine, glycine and contain few hydroxyproline residues (0.91–2.44% total amino acid content). The use of cellulase does not significantly improve the extraction of algal proteins in comparison with the blank procedure (without enzymes). The weak accessibility of the substrates in the intact cell wall could explain these experimental data. The improvement of protein yield after the use of the polysaccharidase mixture (-glucanase, hemicellulase, cellulase) partially confirms this hypothesis.
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