The growing shortage of fossil fuels caused an increase in the demand for alternative and renewable fuels. Biofuels, like bioethanol and biodiesel, have received more attention as a sustainable replacement of fossil fuels. However, these have a poor oxidative stability, little energy content by volume, and many oxygenated compounds, which may cause corrosion and damage to the engines. Therefore, they are used as a mixture with standard fuels. Some species of microalgae are candidates to produce oils as triglycerides (TGA) to produce biodiesel by transesterification; however, the problem will remain. The colonial microalgae Botryococcus braunii produces and accumulates a high amount of long-chain nonoxygenated hydrocarbons, similar to those obtained from the fractionated distillation of crude petroleum. This is one of the few organisms reported to have a direct contribution in the formation of the oil reserves currently in use. Additionally, B. braunii produces pigments and long-chain carbohydrates that have interesting properties for various industries. There are still problems to be solved in order to consider it as economically viable and profitable, but important progress is being made. Therefore, this microalga is very attractive for the synthesis of hydrocarbons and other value-added compounds, making it an interesting biorefinery organism.

Botryococcus braunii produce liquid hydrocarbons able to be processed into combustion engine fuels. Depending on the growing conditions, the cell doubling time can be up to 6 days or more, which is a slow growth rate in comparison with other microalgae. Few studies have analyzed the cell cycle of B. braunii. We did a bioinformatic comparison between the protein sequences for retinoblastoma and cyclin-dependent kinases from the A (Yamanaka) and B (Showa) races, with those sequences from other algae and Arabidopsis thaliana. Differences in the number of cyclin-dependent kinases and potential retinoblastoma phosphorylation sites between the A and B races were found. Some cyclin-dependent kinases from both races seemed to be phylogenetically more similar to A. thaliana than to other microalgae. Microscopic observations were done using several staining procedures. Race A colonies, but not race B, showed some multinucleated cells without chlorophyll. An active mitochondrial net was detected in those multinucleated cells, as well as being defined in polyphosphate bodies. These observations suggest differences in the cell division processes between the A and B races of B. braunii.