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Genomics of microalgae, fuel for the future?

Brooijmans RJ, Siezen RJ - Microb Biotechnol (2010)

View Article: PubMed Central - PubMed

Affiliation: B-Basic, 2628 BC Delft, the Netherlands.

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First‐ and second‐generation biofuels envision the conversion of plant biomass via the action of microorganisms, into usable organic compounds (alcohols and fats) and hydrogen... In general, microalgae do not comprise an evolutionarily related group, and may refer to cyanobacteria (blue‐green algae) or eukaryotic algae... Furthermore, algae can be grown everywhere where there is plenty of water and sun (including lakes or in the sea) and thus are not necessarily restricted to (or compete with) areas with arable land... Combined with their fast growth rate, microalgae are considered one of the few realistic sources for the production of biofuels and superior to agricultural crop‐derived bioethanol... Nevertheless, the two major classes of diatoms are represented: the bi/multipolar centrics (Thalassiosira pseudonana) and the pennates (Phaeodactylum tricornutum)... About 57% of the genes found in P. tricornutum have homologues in T. pseudonana and both have acquired a remarkable number of bacterial genes (after secondary endosymbiosis), a degree of magnitude higher than found in other free living eukaryotes... These include genes encoding silicic acid transporters, many spermidine and spermine synthase‐like enzymes, silaffins and frustulins (casing glycoproteins)... Up to fourfold more genes putatively encoding spermidine and spermine synthases can be found in diatom genomes than in other organisms... Chitin fibres, extending from the silica cage, are thought to limit sinking and can account for up to 40% of the biomass... Many diatom‐specific cyclins were also found in the genomes of P. tricornutum and T. pseudonana... For all its beauty, the actual function of the silica shell remains somewhat unclear... It may reduce predation by grazers... In addition to growing diatoms as algae for biofuels, the discovery of the genes that are associated with the silica cage formation may provide handles for future manipulation of the silica nanostructure to catalyse nanobiotechnological applications... Despite the growing number of completed microalgae genome sequences, only a few examples of genetic engineering of the metabolism for the production of biofuels are reported... The immediate future for metabolic engineering with microalgae may lie in the (over)production of high‐value chemicals or biomass components.

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Evolutionary relationships of 20 species with sequenced genomes used for comparative analyses, including cyanobacteria and non‐photosynthetic eubacteria, archaea and eukaryotes from the oomycetes, diatoms, rhodophytes, plants, amoebae and opisthokonts (Keeling et al., 2005; Ciccarelli et al., 2006). Endosymbiosis of a cyanobacterium by a eukaryotic protist gave rise to the green (green branches) and red (red branches) plant lineages respectively. The presence of motile or non‐motile flagella is indicated at the right of the cladogram. Reprinted from Merchant and colleagues (2007) with permission from AAAS.
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f1: Evolutionary relationships of 20 species with sequenced genomes used for comparative analyses, including cyanobacteria and non‐photosynthetic eubacteria, archaea and eukaryotes from the oomycetes, diatoms, rhodophytes, plants, amoebae and opisthokonts (Keeling et al., 2005; Ciccarelli et al., 2006). Endosymbiosis of a cyanobacterium by a eukaryotic protist gave rise to the green (green branches) and red (red branches) plant lineages respectively. The presence of motile or non‐motile flagella is indicated at the right of the cladogram. Reprinted from Merchant and colleagues (2007) with permission from AAAS.

Mentions: Rising sea levels, global pollution, economic meltdown and general prophecies of doom and gloom are inspired by the pending depletion of the world fossil carbon stores. With modern lifestyle on the rise, and an ever increasing world population driven on by economic advantage, we burn up earth's stores of mineralized corpses and vent CO2 as if there is no tomorrow. The billion dollar question for our society is: Where to get the next big, and preferably clean, fuel injection? Fossil carbon compounds, the incompletely biodegraded remains of animals and plants long gone, originate from atmospheric CO2 via photosynthesis. Therefore, photosynthesis as main driver for generation of de novo fuels has gained attention. First‐ and second‐generation biofuels envision the conversion of plant biomass via the action of microorganisms, into usable organic compounds (alcohols and fats) and hydrogen. However, water and land misuse, deforestation, and rising food prices, for the sake of growing choice biomass‐producing crops, have raised major concerns (Frow et al., 2009; Young, 2009). Third‐generation biofuels (and chemicals) produced with microalgae have now come forward as an answer to many of these concerns (Tredici, 2010). In general, microalgae do not comprise an evolutionarily related group, and may refer to cyanobacteria (blue‐green algae) or eukaryotic algae. Even the eukaryotic algae do not form a single evolutionary branch as it can be used to indicate ‘plant algae’ such as red algae (Rhodophyta), brown algae (Phaetophyta) and green algae (Chlorophyta) or diatoms (Fig. 1).


Genomics of microalgae, fuel for the future?

Brooijmans RJ, Siezen RJ - Microb Biotechnol (2010)

Evolutionary relationships of 20 species with sequenced genomes used for comparative analyses, including cyanobacteria and non‐photosynthetic eubacteria, archaea and eukaryotes from the oomycetes, diatoms, rhodophytes, plants, amoebae and opisthokonts (Keeling et al., 2005; Ciccarelli et al., 2006). Endosymbiosis of a cyanobacterium by a eukaryotic protist gave rise to the green (green branches) and red (red branches) plant lineages respectively. The presence of motile or non‐motile flagella is indicated at the right of the cladogram. Reprinted from Merchant and colleagues (2007) with permission from AAAS.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3815765&req=5

f1: Evolutionary relationships of 20 species with sequenced genomes used for comparative analyses, including cyanobacteria and non‐photosynthetic eubacteria, archaea and eukaryotes from the oomycetes, diatoms, rhodophytes, plants, amoebae and opisthokonts (Keeling et al., 2005; Ciccarelli et al., 2006). Endosymbiosis of a cyanobacterium by a eukaryotic protist gave rise to the green (green branches) and red (red branches) plant lineages respectively. The presence of motile or non‐motile flagella is indicated at the right of the cladogram. Reprinted from Merchant and colleagues (2007) with permission from AAAS.
Mentions: Rising sea levels, global pollution, economic meltdown and general prophecies of doom and gloom are inspired by the pending depletion of the world fossil carbon stores. With modern lifestyle on the rise, and an ever increasing world population driven on by economic advantage, we burn up earth's stores of mineralized corpses and vent CO2 as if there is no tomorrow. The billion dollar question for our society is: Where to get the next big, and preferably clean, fuel injection? Fossil carbon compounds, the incompletely biodegraded remains of animals and plants long gone, originate from atmospheric CO2 via photosynthesis. Therefore, photosynthesis as main driver for generation of de novo fuels has gained attention. First‐ and second‐generation biofuels envision the conversion of plant biomass via the action of microorganisms, into usable organic compounds (alcohols and fats) and hydrogen. However, water and land misuse, deforestation, and rising food prices, for the sake of growing choice biomass‐producing crops, have raised major concerns (Frow et al., 2009; Young, 2009). Third‐generation biofuels (and chemicals) produced with microalgae have now come forward as an answer to many of these concerns (Tredici, 2010). In general, microalgae do not comprise an evolutionarily related group, and may refer to cyanobacteria (blue‐green algae) or eukaryotic algae. Even the eukaryotic algae do not form a single evolutionary branch as it can be used to indicate ‘plant algae’ such as red algae (Rhodophyta), brown algae (Phaetophyta) and green algae (Chlorophyta) or diatoms (Fig. 1).

View Article: PubMed Central - PubMed

Affiliation: B-Basic, 2628 BC Delft, the Netherlands.

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

First‐ and second‐generation biofuels envision the conversion of plant biomass via the action of microorganisms, into usable organic compounds (alcohols and fats) and hydrogen... In general, microalgae do not comprise an evolutionarily related group, and may refer to cyanobacteria (blue‐green algae) or eukaryotic algae... Furthermore, algae can be grown everywhere where there is plenty of water and sun (including lakes or in the sea) and thus are not necessarily restricted to (or compete with) areas with arable land... Combined with their fast growth rate, microalgae are considered one of the few realistic sources for the production of biofuels and superior to agricultural crop‐derived bioethanol... Nevertheless, the two major classes of diatoms are represented: the bi/multipolar centrics (Thalassiosira pseudonana) and the pennates (Phaeodactylum tricornutum)... About 57% of the genes found in P. tricornutum have homologues in T. pseudonana and both have acquired a remarkable number of bacterial genes (after secondary endosymbiosis), a degree of magnitude higher than found in other free living eukaryotes... These include genes encoding silicic acid transporters, many spermidine and spermine synthase‐like enzymes, silaffins and frustulins (casing glycoproteins)... Up to fourfold more genes putatively encoding spermidine and spermine synthases can be found in diatom genomes than in other organisms... Chitin fibres, extending from the silica cage, are thought to limit sinking and can account for up to 40% of the biomass... Many diatom‐specific cyclins were also found in the genomes of P. tricornutum and T. pseudonana... For all its beauty, the actual function of the silica shell remains somewhat unclear... It may reduce predation by grazers... In addition to growing diatoms as algae for biofuels, the discovery of the genes that are associated with the silica cage formation may provide handles for future manipulation of the silica nanostructure to catalyse nanobiotechnological applications... Despite the growing number of completed microalgae genome sequences, only a few examples of genetic engineering of the metabolism for the production of biofuels are reported... The immediate future for metabolic engineering with microalgae may lie in the (over)production of high‐value chemicals or biomass components.

Show MeSH
Related in: MedlinePlus