1 Chlorophylls in Microalgae: Occurrence …
3
The structure of chlorophyll a (Chl a) was established in the forties according
to information in Fischer and Strell (1947) that report research by the groups of
Hans Fischer and James Conant (Fischer and Orth 1940) as important contributions.
Chlorophylls can be defined as cyclic tetrapyrroles carrying a characteristic isocyclic
five-membered ring that are functional in light harvesting or in charge separation in
photosynthesis (Sheer 2006). Due to high absorption and long-lived excited states,
chlorophylls are powerful photosensitizers. The safe transduction of this excited state
into chemical energy is the basis of photosynthesis. Fischer and co-workers were the
first to delineate the structure of the porphyrin ring, both deductively and by synthesis
(Fisher and Orth 1937), as well as the fine structure of the degradation products which
Professor Willstätter had prepared. He has been considered the father of the modern
era on the study of chlorophyll chemistry with most of his research being summarized
in “Untersuchungen über Chlorophyll” (Willstätter and Stoll 1913). Stokes (1854,
1864a, 1864b) suggested that chlorophyll consisted of two components and that the
green fluorescent residue that remained after extraction of carotenoids would still
be a mixture of two green substances that fluoresce in the red (Aronoff 1966). It
dates of 1906–1908 by Tswett (1906, 1907, 1908) that the physical proof of the
existence of two chlorophylls in green leaves had been demonstrated. This was
possible with the advent of adsorption chromatography. In the very beginning of
chlorophyll research, publications by Hoppe-Seyler (1879, 1880, 1881), Nencki and
co-workers (Nencki and Zaleski 1901, Nencki and Marchlewski 1901), and Borodin
(1882) had an important role in understanding the chlorophylls. Monteverde (1893)
isolated the crystalline chlorophylls and determined their spectroscopic properties.
It was Nencki in 1896 that predicted the similar chemical properties of chlorophyll
(Mg) and heme (Fe), what would denote a common origin of plant and animal life.
Moreover, Nencki (1896) proposed that comparison of similar compounds of flora
and fauna would provide insights into the chemical and organismal evolution in
nature.
Microalgae are a general name for a diverse polyphyletic group of microorganisms
that convert sunlight into chemical energy through photosynthesis. A complex set of
pigments that in addition to chlorophylls (Chl), can include carotenes, xanthophylls,
and in some algal groups the biliproteins phycocyanin and phycoerythrin, contribute
to optimization of light absorption during photosynthesis. The chlorophylls (Chl)
and their absorption maximum (solved in methanol) that have been described in
photosynthetic organisms are Chl a (the most abundant, 665 nm), Chl b (652 nm),
Chl c (630 nm), Chl d (696 nm), and more recently Chl f (707 nm) (Chen et al. 2010,
Chen et al. 2012, Chen 2014, Ferreira and Sant’Anna 2017). Chlorophyll f has been
identified just in Cyanobacteria (Chen et al. 2012).
In the present chapter we concentrate on chlorophylls, focusing on their origin,
distribution, and occurrence, including a short overview of its biosynthesis.
3
The structure of chlorophyll a (Chl a) was established in the forties according
to information in Fischer and Strell (1947) that report research by the groups of
Hans Fischer and James Conant (Fischer and Orth 1940) as important contributions.
Chlorophylls can be defined as cyclic tetrapyrroles carrying a characteristic isocyclic
five-membered ring that are functional in light harvesting or in charge separation in
photosynthesis (Sheer 2006). Due to high absorption and long-lived excited states,
chlorophylls are powerful photosensitizers. The safe transduction of this excited state
into chemical energy is the basis of photosynthesis. Fischer and co-workers were the
first to delineate the structure of the porphyrin ring, both deductively and by synthesis
(Fisher and Orth 1937), as well as the fine structure of the degradation products which
Professor Willstätter had prepared. He has been considered the father of the modern
era on the study of chlorophyll chemistry with most of his research being summarized
in “Untersuchungen über Chlorophyll” (Willstätter and Stoll 1913). Stokes (1854,
1864a, 1864b) suggested that chlorophyll consisted of two components and that the
green fluorescent residue that remained after extraction of carotenoids would still
be a mixture of two green substances that fluoresce in the red (Aronoff 1966). It
dates of 1906–1908 by Tswett (1906, 1907, 1908) that the physical proof of the
existence of two chlorophylls in green leaves had been demonstrated. This was
possible with the advent of adsorption chromatography. In the very beginning of
chlorophyll research, publications by Hoppe-Seyler (1879, 1880, 1881), Nencki and
co-workers (Nencki and Zaleski 1901, Nencki and Marchlewski 1901), and Borodin
(1882) had an important role in understanding the chlorophylls. Monteverde (1893)
isolated the crystalline chlorophylls and determined their spectroscopic properties.
It was Nencki in 1896 that predicted the similar chemical properties of chlorophyll
(Mg) and heme (Fe), what would denote a common origin of plant and animal life.
Moreover, Nencki (1896) proposed that comparison of similar compounds of flora
and fauna would provide insights into the chemical and organismal evolution in
nature.
Microalgae are a general name for a diverse polyphyletic group of microorganisms
that convert sunlight into chemical energy through photosynthesis. A complex set of
pigments that in addition to chlorophylls (Chl), can include carotenes, xanthophylls,
and in some algal groups the biliproteins phycocyanin and phycoerythrin, contribute
to optimization of light absorption during photosynthesis. The chlorophylls (Chl)
and their absorption maximum (solved in methanol) that have been described in
photosynthetic organisms are Chl a (the most abundant, 665 nm), Chl b (652 nm),
Chl c (630 nm), Chl d (696 nm), and more recently Chl f (707 nm) (Chen et al. 2010,
Chen et al. 2012, Chen 2014, Ferreira and Sant’Anna 2017). Chlorophyll f has been
identified just in Cyanobacteria (Chen et al. 2012).
In the present chapter we concentrate on chlorophylls, focusing on their origin,
distribution, and occurrence, including a short overview of its biosynthesis.