4. Conclusions

Although B. braunii has been considered mainly as a good source of biofuels by the possibility to convert its hydrocarbons into currently used fuels, without the necessity of engine modifications, it produces many other high-value derivatives that can be exploited for their promising attractive profits. Besides, along the photosynthetic process, this alga converts 3% of solar energy into hydrocarbons [1] and can reduce CO2 emissions up to 1.5 <sup>10</sup><sup>5</sup> tons/year [113]. There are several reports about modifications of the culture conditions through vitamin addition, affecting the yield of several derivatives like biomass, hydrocarbon, and carbohydrate in Botryococcus braunii KMITL 5 [114]; however, those are from not clearly recognized strains and should be carefully taken. With B. braunii race A, B, or L, the main challenge is to accelerate the doubling rate because, depending on the race, it varies between 2 and 10 days. This results in easy contamination with faster growing microorganisms in open ponds used for industrial production, or a high cost of sterile conditions in closed bioreactors. In spite of these disadvantages, we consider that B. braunii is an excellent model of biorefinery. Other strategies to use B. braunii as biorefinery and bioreactor are being developed like the immobilization in polyester [115] or bioharvesting with Aspergillus sp. [116].
