We disclose a process to produce carbon nanotubes from microalgae. Microalgae is been utilized for biodiesel production. The algal membrane resulted from oil extraction of microalgae is used here to produce carbon nanotubes. The process utilized for the conversion is composed of two steps, in the first step the algal membrane is converted to carbon black through a pyrolysis process in inert atmosphere, in the second step the resulted carbon black is converted to carbon nanotubes by mixing the carbon black with a fluid with known self ignition condition and subjecting the mix to said self ignition condition.