Spirulina is a cyan bacterium that can be consumed by humans and other animals and is made primarily from two species of cyan bacterium : Arthrospira platensis and Arthrospira maxima . Spirulina is simple one-celled microscopic blue -green algae with the scientific name Arthrospira platensis. Under a microscope, spirulina appears as long, thin, blue-green spiral threads. The odor and taste of spirulina is similar to seaweed. Spirulina can be found in many freshwater environments, including ponds, lakes, and rivers. It thrives best under pesticide-free conditions with plenty of sunlight and moderate temperature levels, but it is also highly adaptable, surviving even in extreme conditions. There remain some basic reasons behind the choice of spirulina as the production substance ....a) Spirulina is the most easily collectable algae than others in Bangladesh b) According to the availability and easily collectability spirulina is the lowest cost algae than others. c)with the present work for algal fuel in Bangladesh, spirulina is the most common one for the technology is available here. BCSIR and CARS and some laboratories in BUET have the known facility to work with spirulina and widespread expertise knowledge is available for this.