Abstract

                                Botryococcus braunii is notable for its ability to produce high amounts ofhydrocarbons, especially oils in the form of triterpenes. Samples of greencolonial unicellular microalga B. braunii were collected from Kuruchi lakeat Coimbatore. The culture was initially screened and purifed. Basedon the macroscopic and microscopic studies, the purifed culture wasidentifed as B. brauni. Macroscopic characters like clumpy, green colonieswere produced by B.braunii on BG-11 medium. The colony characterslike green, pyramid-shaped colloidal microalgae were observed. Studieswere conducted to determine the effect of pH, sodium-bi-carbonate, darkand light, and to estimate the chlorophyll, lipid, sugar and protein contentby the isolate. The culture attains log phase at third week. The growthof Botryococcus is observed to be maximum in pH 7 and a high yield ofbiomass produced at this pH. When 2.5% sodium-bi-carbonate is addedalong with the medium, the growth curve attains a log phase on the 6th dayitself. The Botryococcus exposed to 24 hour light conditions showed animproved growth rate compared to Botryococcus exposed to 16 hours light.The amount of chlorophyll is 0.039% occurs in 100gm of Botryococcus. Themaximum amount of protein was observed in hexane extract is 50%, andthe mutagenesis for 30 minutes results in 55.6%. The maximum amount oflipid was observed in hexane extract is 16.5%, and the mutagenesis for 30minutes results in 38.9%. The maximum amount of sugar was observed inethanol extract is 78.15%, and the mutagenesis for 40 minutes results in58.3% while extracting with hexane.

Key words : Biofuel; Botryococcus; optimization; lipid yield