Botryococcus braunii
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| Botryococcus braunii | ||||||||||||||
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| Botryococcus braunii Kützing |
Botryococcus braunii (Bb) is a green, pyramid shaped planktonic microalga of the order Chlorococcales (class Chlorophyceae) 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 oligotrophic 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.[1] Compared to other green algae species it has a relatively thick cell wall that is accumulated from previous cellular divisions; making extraction of cytoplasmic components rather difficult. Fortunately, much of the useful hydrocarbon oil is outside of the cell.
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[edit] 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.[2] However, this was the results of testing with one strain, others certainly vary to some degree.
[edit] Biofuel applications of botryococcene
The practice of farming cultivating is known as algaculture. 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 [3]. The vast majority of these hydrocarbons are oils called botryococcenes. Transesterification can NOT be used to make biodiesel from botryococcenes. This is because botryococcenes are not 'vegetable oils' in the common meaning, in which they are fatty acid triglycerides. While botryococcenes are oils of vegetable origin, they are inedible and chemically very different, being triterpenes, and lack the free oxygen atom needed for transesterification. Botryococcenes can be used as feedstock for hydrocracking in an oil refinery to produce octane (gasoline, a.k.a. petrol), kerosene, and diesel.[4]
[edit] Oils
Two major races of Bb are known, and they are distinguished by the structure of their botryococcene hydrocarbons. Botryococcenes are unbranched isoprenoid triterpenes having the formula CnH2n-10. The A race produces botryococcenses wherein n is an odd number 23 through 31. The B race produces botryococcenes wherein n is in the range 30 through 37, inclusive. Within this major classification, various strains of Bb will differ in the precise structure and concentrations of the constituent hydrocarbons.[5]
According to p. 30 on Aquatic Species Program (ASP) report,[6] 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.[2] The ASP also found 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.
| 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
[edit] Botryococcus braunii Specimen Sources
The prices below are subject to change, and many organizations have restrictions and special pricing regimes. None of the prices include shipping costs.
- SERI US strain BOTRY1
- CCALA CZ strains DROOP 1950, HEGEWALD 1977, SANTOS 1975, SANTOS 1997 €13
- CCAC DE strain CCAC02129 (Vienna 1997) €30 non-profit, €100 commercial - cannot resell to other parties
- SAG DE strains DROOP 1950, HEGEWALD 1977 €12.50 subsidized rate, €50 standard rate
- MCC-NIES JP strain KAGOSHIMA 1997 ¥6000 academic, ¥10000 commercial
- CCAP UK strains DROOP 1950, JAWORSKI 1984 £30 non-profit, £60 commercial
- UTEX US strains HEGEWALD 1977, DROOP 1950 $30 US Government and Academic, $75 commercial
- ACOI PT strains SANTOS 1975, SANTOS 1997 €10 academic inside Portugal, €20 other academic, €50 commercial
- BCC US has been 'coming soon' for some time now $15 academic, $50 commercial
See also List of microalgae culture collections.
[edit] Patented strains
In 1986, UCBerkeley was granted US Plant Patent 6169 for the Showa variety of Botryococcus braunii, developed by UC Berkeley scientist Dr. Arthur Nonomura. Their proprietary variety was notable, says the patent application, because of its fast growth rate and high oil content. However, it is not clear as to whether Bb Showa was in fact more productive than strains which have been subsequently identified. The patent expired in April 2006.
In May 2006, Dr. Nonomura filed an international patent application with a large number of claims relating to Botryococcus braunii culturing, including a claim for a variety named Ninsei. Rights to this yet ungranted patent were immediately purchased by Kwikpower International from Plenty Energy, Inc., a company founded by Dr. Nonomura.
[edit] References
- ^ P. Metzger C. Largeau (2005). "Botryococcus braunii: a rich source for hydrocarbons and related ether lipids". Applied Microbiology and Biotechnology 6 (25): 486–496. doi:.
- ^ a b Jian Qin (2005). "Bio -Hydrocarbons from Algae: Impacts of temperature, light and salinity on algae growth". . Rural Industries Research and Development Corporation, Australia
- ^ Algal Oil Yields – Yield Data for Oil from Algae Strains, Algae Species with High Oil Yields
- ^ a b L.W. Hillen "et al." (1982). "Hydrocracking of the Oils of Botryococcus braunii to Transport Fuels". Biotechnology and Bioengineering 24: 193–205. doi:.
- ^ J. Frenz "et al." (1989). "Hydrocarbon Recovery and Biocompatibility of Solvents for Extraction from Cultures of Botryococcus braunii". Biotechnology and Bioengineering 34: 755–762. doi:.
- ^ www.eere.energy.gov Department of Energy Aquatic Species Program; Biodiesel Production from Algae.(pdf)
[edit] External links
- Botryococcus braunii Kütz.. NIES Japan. Retrieved on 2008-01-09. Image of B. braunii.
