Botryococcus braunii
Encyclopedia
Botryococcus braunii is a green, pyramid shaped planktonic
microalga that is of potentially great importance in the field of biotechnology
. Colonies held together by a lipid biofilm matrix can be found in temperate or tropical oligotroph
ic lakes and estuaries, and will bloom when in the presence of elevated levels of dissolved inorganic phosphorus. The species is notable for its ability to produce high amounts of hydrocarbons, especially oils in the form of Triterpenes, that are typically around 30-40 percent of their dry weight. Compared to other green algae species it has a relatively thick cell wall that is accumulated from previous cellular divisions; making extraction of cytoplasm
ic components rather difficult. Fortunately, much of the useful hydrocarbon oil is outside of the cell.
medium .
. Botryococcus braunii has great potential for algaculture because of the hydrocarbons it produces, which can be chemically converted into fuels. Up to 86% of the dry weight of Botryococcus braunii can be long chain hydrocarbons . The vast majority of these hydrocarbons are botryocuccus oils: botryococcenes, alkadienes and alkatrienes. Transesterification
can NOT be used to make biodiesel
from Botryococcus oils. This is because these oils are not vegetable oils in the common meaning, in which they are fatty acid
triglycerides. While Botryococcus oils are oils of vegetable origin, they are inedible and chemically very different, being triterpenes, and lack the free oxygen atom needed for transesterification. Botryococcus oils can be used as feedstock for hydrocracking in an oil refinery
to produce octane (gasoline
, a.k.a. petrol), kerosene
, and diesel. (see vegetable oil refining
). Botryococcenes are preferred over alkadienes and alkatrienes for hydrocracking as botryococcenes will likely be transformed into a fuel with a higher octane rating
.
According to page 30 on Aquatic Species Program
(ASP) report, the A-strain of Botryococcus would not function well as a feedstock for lipid based fuel production due to its slow growth (one doubling every 72 hours). However, subsequent research by Qin showed that the doubling time could be reduced to 48 hours in its optimal growth environment. In view of findings by Frenz , the doubling times may not be as important as the method of hydrocarbon harvest. The ASP also found A-strain Botryococcus oil to be less than ideal, having most of its lipids as C29 to C34 aliphatic hydrocarbons, and less abundance of C18 fatty acids. This evaluation of Bb oils was done in relation to their suitability for transesterification
(i.e. creating biodiesel
), which was the focus of the ASP at the time Bb was evaluated. The ASP did not study Bb oils for their suitability in hydrocracking, as some subsequent studies have done on the "B" race.
The two listed C36H62 entries are not typos; they are for two different isomers
In 1988, UCBerkeley
was granted US Plant Patent 6169 for Botryococcus braunii variety Showa, developed by UC Berkeley scientist Arthur Nonomura, in the Melvin Calvin Laboratory as part of the Nobel laureate's groundbreaking interdisciplinary program for the development of renewable transport fuels. The proprietary variety was notable, says the patent application, because of its highly reproducible botryococcenes hydrocarbon content comprising 20% of the dry weight of "Showa." It is clear that Showa was borne out as the top source of hydrocarbons of its time. The patent expired in April 2008.
In May 2006, Nonomura filed an international patent application disclosing novel growth and harvesting processes for the Chlorophyta. A separate patent for plants is also filed on Botryococcus braunii variety Ninsei that exhibits the feature of extracolonial secretion of it botryococcenoids that can be processed in existing gasoline refineries to transport fuels.
In August 2011, variety Enomoto was announced by IHI NeoG Algae LLC . It has "...the highest yield for this fuel production over all the algae that have been discovered in the world", with a claimed monthly growth a thousand times higher than normal Bb strains. It is additionally said to be very robust , presumably meaning it could be grown in an open environment (in ponds, instead of photobioreactors).
Plankton
Plankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...
microalga that is of potentially great importance in the field of biotechnology
Biotechnology
Biotechnology is a field of applied biology that involves the use of living organisms and bioprocesses in engineering, technology, medicine and other fields requiring bioproducts. Biotechnology also utilizes these products for manufacturing purpose...
. Colonies held together by a lipid biofilm matrix can be found in temperate or tropical oligotroph
Oligotroph
An oligotroph is an organism that can live in an environment that offers very low levels of nutrients. They may be contrasted with copiotrophs, which prefer nutritionally rich environments...
ic lakes and estuaries, and will bloom when in the presence of elevated levels of dissolved inorganic phosphorus. The species is notable for its ability to produce high amounts of hydrocarbons, especially oils in the form of Triterpenes, that are typically around 30-40 percent of their dry weight. Compared to other green algae species it has a relatively thick cell wall that is accumulated from previous cellular divisions; making extraction of cytoplasm
Cytoplasm
The cytoplasm is a small gel-like substance residing between the cell membrane holding all the cell's internal sub-structures , except for the nucleus. All the contents of the cells of prokaryote organisms are contained within the cytoplasm...
ic components rather difficult. Fortunately, much of the useful hydrocarbon oil is outside of the cell.
Optimal growth environment
Botryococcus braunii has been shown to grow best at a temperature of 23°C, a light intensity of 60 W/M², with a light period of 12 hours per day, and a salinity of 0.15 Molar NaCl. However, this was the results of testing with one strain, and others certainly vary to some degree. In the laboratory, B. braunii is commonly grown in cultures of Chu 13Chu 13
CHU 13 medium is a culture medium used in microbiology for the growth of certain algal species, first published by S.P. Chu in 1942. It is used as growth medium for the biofuel candidate alga Botryococcus braunii....
medium .
Toxic blooms and competition
Blooms of Botryococcus braunii have been shown to be toxic to other micro-organisms and fishes. The cause of the blooms and their subsequent damage to the populations of other organisms has been studied. The exudate of Bb in the form of free fatty acids has been identified as the cause. A higher alkalinity changes these free fatty acids into a form which is more toxic to other species, thus causing Bb to become more dominant. Higher alkalinity often occurs when ashes from burned areas are washed into a body of water. While the dominance of Bb can be seen as damaging to the environmental diversity of a body of water, the knowledge of how Bb can gain and maintain dominance is useful to those who intend to grow ponds of it as a fuel crop.Biofuel applications of Botryococcus oils
The practice of farming cultivating is known as algacultureAlgaculture
Algaculture is a form of aquaculture involving the farming of species of algae.The majority of algae that are intentionally cultivated fall into the category of microalgae...
. Botryococcus braunii has great potential for algaculture because of the hydrocarbons it produces, which can be chemically converted into fuels. Up to 86% of the dry weight of Botryococcus braunii can be long chain hydrocarbons . The vast majority of these hydrocarbons are botryocuccus oils: botryococcenes, alkadienes and alkatrienes. Transesterification
Transesterification
In organic chemistry, transesterification is the process of exchanging the organic group R″ of an ester with the organic group R′ of an alcohol. These reactions are often catalyzed by the addition of an acid or base catalyst...
can NOT be used to make biodiesel
Biodiesel
Biodiesel refers to a vegetable oil- or animal fat-based diesel fuel consisting of long-chain alkyl esters. Biodiesel is typically made by chemically reacting lipids with an alcohol....
from Botryococcus oils. This is because these oils are not vegetable oils in the common meaning, in which they are fatty acid
Fatty acid
In chemistry, especially biochemistry, a fatty acid is a carboxylic acid with a long unbranched aliphatic tail , which is either saturated or unsaturated. Most naturally occurring fatty acids have a chain of an even number of carbon atoms, from 4 to 28. Fatty acids are usually derived from...
triglycerides. While Botryococcus oils are oils of vegetable origin, they are inedible and chemically very different, being triterpenes, and lack the free oxygen atom needed for transesterification. Botryococcus oils can be used as feedstock for hydrocracking in an oil refinery
Oil refinery
An oil refinery or petroleum refinery is an industrial process plant where crude oil is processed and refined into more useful petroleum products, such as gasoline, diesel fuel, asphalt base, heating oil, kerosene, and liquefied petroleum gas...
to produce octane (gasoline
Gasoline
Gasoline , or petrol , is a toxic, translucent, petroleum-derived liquid that is primarily used as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. Some gasolines also contain...
, a.k.a. petrol), kerosene
Kerosene
Kerosene, sometimes spelled kerosine in scientific and industrial usage, also known as paraffin or paraffin oil in the United Kingdom, Hong Kong, Ireland and South Africa, is a combustible hydrocarbon liquid. The name is derived from Greek keros...
, and diesel. (see vegetable oil refining
Vegetable oil refining
Vegetable oil can be used as feedstock for an oil refinery. There it can be transformed into fuel by hydrocracking or hydrogenation . These methods can produce gasoline, diesel, and propane. Some commercial examples of vegetable oil refining are NExBTL, H-Bio, and the ConocoPhilips process...
). Botryococcenes are preferred over alkadienes and alkatrienes for hydrocracking as botryococcenes will likely be transformed into a fuel with a higher octane rating
Octane rating
Octane rating or octane number is a standard measure of the anti-knock properties of a motor or aviation fuel. The higher the octane number, the more compression the fuel can withstand before detonating...
.
Oils
Three major races of Botryococcus braunii are known, and they are distinguished by the structure of their oils. Botryococcenes are unbranched isoprenoid triterpenes having the formula CnH2n-10. The A race produces alkadienes and alkatrienes (derivatives of fatty acids) wherein n is an odd number 23 through 31. The B race produces botryococcenes wherein n is in the range 30 through 37 biofuels of choice for hydrocracking to gasoline-type hydrocarbons. The "L" strain makes an oil not formed by other strains of Botryococcus braunii. Within this major classification, various strains of Botryococcus will differ in the precise structure and concentrations of the constituent hydrocarbons oils.According to page 30 on Aquatic Species Program
Aquatic Species Program
The Aquatic Species Program was a research program in the United States launched in 1978 by President Jimmy Carter and was funded by the United States Department of Energy, which over the course of nearly two decades looked into the production of energy using algae. Initially, the funding of the...
(ASP) report, the A-strain of Botryococcus would not function well as a feedstock for lipid based fuel production due to its slow growth (one doubling every 72 hours). However, subsequent research by Qin showed that the doubling time could be reduced to 48 hours in its optimal growth environment. In view of findings by Frenz , the doubling times may not be as important as the method of hydrocarbon harvest. The ASP also found A-strain Botryococcus oil to be less than ideal, having most of its lipids as C29 to C34 aliphatic hydrocarbons, and less abundance of C18 fatty acids. This evaluation of Bb oils was done in relation to their suitability for transesterification
Transesterification
In organic chemistry, transesterification is the process of exchanging the organic group R″ of an ester with the organic group R′ of an alcohol. These reactions are often catalyzed by the addition of an acid or base catalyst...
(i.e. creating biodiesel
Biodiesel
Biodiesel refers to a vegetable oil- or animal fat-based diesel fuel consisting of long-chain alkyl esters. Biodiesel is typically made by chemically reacting lipids with an alcohol....
), which was the focus of the ASP at the time Bb was evaluated. The ASP did not study Bb oils for their suitability in hydrocracking, as some subsequent studies have done on the "B" race.
| Compound | % mass |
|---|---|
| Isobotryococcene | 4% |
| Botryococcene | 9% |
| C34H58 | 11% |
| C36H62 | 34% |
| C36H62 | 4% |
| C37H64 | 20% |
| Other hydrocarbons | 18% |
The two listed C36H62 entries are not typos; they are for two different isomers
Research
Due to the burgeoning interest in alternatives to fossil fuels, there has been renewed research interest in Botryococcus braunii. The DOE Joint Genome Institute is sequencing the DNA of Bb in 2009-2010.Potentially useful strains
This heading is a collection of strains of note because of their potential utility. Some of these strains are patented, some are not. Some are the result of active DNA modification, some are the result of traditional selection processes.In 1988, UCBerkeley
University of California, Berkeley
The University of California, Berkeley , is a teaching and research university established in 1868 and located in Berkeley, California, USA...
was granted US Plant Patent 6169 for Botryococcus braunii variety Showa, developed by UC Berkeley scientist Arthur Nonomura, in the Melvin Calvin Laboratory as part of the Nobel laureate's groundbreaking interdisciplinary program for the development of renewable transport fuels. The proprietary variety was notable, says the patent application, because of its highly reproducible botryococcenes hydrocarbon content comprising 20% of the dry weight of "Showa." It is clear that Showa was borne out as the top source of hydrocarbons of its time. The patent expired in April 2008.
In May 2006, Nonomura filed an international patent application disclosing novel growth and harvesting processes for the Chlorophyta. A separate patent for plants is also filed on Botryococcus braunii variety Ninsei that exhibits the feature of extracolonial secretion of it botryococcenoids that can be processed in existing gasoline refineries to transport fuels.
In August 2011, variety Enomoto was announced by IHI NeoG Algae LLC . It has "...the highest yield for this fuel production over all the algae that have been discovered in the world", with a claimed monthly growth a thousand times higher than normal Bb strains. It is additionally said to be very robust , presumably meaning it could be grown in an open environment (in ponds, instead of photobioreactors).
See also
- TorbaniteTorbaniteTorbanite, also known as boghead coal, is a variety of fine-grained black oil shale. It usually occurs as lenticular masses, often associated with deposits of Permian coals. Torbanite is classified as lacustrine type oil shale....
, a coal formed from Botryococcus braunii deposits - images of Bb
External links
- Frank Wiegert's critical essay on The Energy Collective holds Botryococcus braunii out as one of the more promising renewable hydrocarbons