Isolation and characterization of hydrocarbon producing green alga Botryococcus braunii from Indian freshwater bodies

Abstract

Samples of green colonial unicellular microalga Botryococcus braunii were collected from Bear Shola Falls at Kodaikanal (latitude 10.31 N and longitude 77.32 E), Tamil Nadu, India. Specimens were isolated, cultured and examined for its hydrocarbon content, morphological features and DNA structural resemblance with the known strain to confirm its identity. Inter simple sequence repeats (ISSR) finger printing revealed strong genetic similarity among the authentic strain (B. braunii N-836) and the Indian isolated strain (B. braunii CFTRI- Bb1) from Kodaikanal. The type of hydrocarbons produced by the Kodaikanal isolates were analyzed and identified as saturated hydrocarbons in the range of C₂₁ to C₃₃ by GCMS. Tetracosane and octacosane were found as the major components among the saturated hydrocarbons produced by this alga, constituting 17.6% and 14.8% respectively. Hydrocarbon content of the organism was in the range of 13-18% of its dry biomass. The fat content of the organism was found to be 22% (w/w). Palmitic and oleic acids were found to be major fatty acids produced by the alga. Lutein and β-carotene were found to be the major carotenoids and constituted about 64.1% and 25.1% respectively of the total carotenoids. Based on ISSR finger printing and hydrocarbon analyses the new algal strain from Kodaikanal was identified as Botryococcus braunii.