Chiang Mai Journal of Science

Botryococcus braunii, a green microalga, has been acknowledged as a possible source of renewable fuel that holds significant potential. However, it has been associated with a slow growth rate and low productivity. Thus, the aim of this study was to investigate the effects of ultraviolet (UV)-C on B. braunii AARL G037 for the purposes of improving biomass, lipid and hydrocarbon production levels. The survival rate was found to be in a range of 0.66-12.54% after being exposed to UV-C radiation for 3-21 minutes. The highest level of biomass production was acquired from UV-C induced isolate no. U18J10 at 2,325.67 mg L-1 and was equivalent to 1.32 times higher than the wild type. The highest hydrocarbon and lipid contents were found in B. braunii U18N14, which were recorded at 76.03% and 34.00%, respectively. Meanwhile, wild type, B. braunii AARL G037 accumulated hydrocarbons and lipids at only 45.81% and 22.70%, respectively. A study on the biodiesel properties revealed that 9-octadecanoic acid, methyl ester (C18:1) was the major fatty acid methyl ester. Moreover, biodiesel properties acquired from B. braunii wild type and all UV-C induced isolates were conformed to the EN14214 standard.