Botryococcus braunii
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Botryococcus braunii (Bb) is a green, pyramid shaped colloidal microalgae of the order tetrasporales (class chlorophyceae) 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 phosphorous. The species is notable for its ability to produce high amounts of Hydrocarbons, especially oils in the form of Fatty Acids, 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] Potential biofuel application
The hydrocarbons this species procures can be chemically converted to biofuels in two distinct processes. First, mono-alkyl esters can be produced by adding an alcohol reactant to the free fatty acids, in the presences of a hydroxide catalyst. This resulting transesterification produces biodiesel which can be used in unconverted diesel engines after blending with petrodiesel. The second process involves(hydrocracked) fatty acid chains that produce molecular compounds of octane (gasoline, a.k.a. petrol), kerosene, and diesel.[3] The chemicals obtained from the hydrocracking of Bb oil are not biodiesel. They are chemically the same as the fuels derived from petroleum.
[edit] Oils of Botryococcus braunii
Two major races of Bb are known, and they are distinguished by the structure of their hydrocarbons. These have the formula CnH2n-10. The A race produces odd, unbranched hydrocarbons n = 23 through 31 and the B race produces n = 30 through 37 isoprenoid hydrocarbons known as Botryococcenes. Within this major classification, various strains of Bb will differ in the precise structure and concentrations of the constituent hydrocarbons. [4]
| Compound | % mass |
|---|---|
| Isobotryococcene | 4% |
| Botryococcene | 9% |
| C34H58 | 11% |
| C36H62 | 34% |
| C36H62 | 4% |
| C37H64 | 20% |
| Other hydrocarbons | 18% |
[edit] Patented Strains
In 1986, UCBerkeley was granted US Plant Patent 6169for a strain of Botryococcus braunii it developed. Their proprietary strain 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. There is no evidence of commercial exploitation of the patent, and it expired in April 2006.
[edit] References
- ^ P. Metzger C. Largeau. "Botryococcus braunii: a rich source for hydrocarbons and related ether lipids". Applied Microbiology and Biotechnology 6 (25): 486-496.
- ^ Jian Qin (2005). "Bio -Hydrocarbons from Algae: Impacts of temperature, light and salinity on algae growth". Rural Industries Research and Development Corporation, Australia.
- ^ a b L.W. Hillen "et al." (1982). "Hydrocracking of the Oils of Botryococcus braunii to Transport Fuels". Biotechnology and Bioengineering 24: 193-205.
- ^ J. Frenz "et al." (1989). "Hydrocarbon Recovery and Biocompatibility of Solvents for Extraction from Cultures of Botryococcus braunii". Biotechnology and Bioengineering 34: 755-762.
[edit] External links
- Botryococcus braunii Kütz.. UTEX Image Bank. Retrieved on 2007-03-02. Image of B. braunii.
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