Low cost medium formulation using cow dung ash for the cultivation of cyanobacterium: Spirulina (Arthrospira) platensis

Abstract

Spirulina (Arthroapira) characterized by helical/spiral shape in open left hand helix is a multicellular, free floating cyanobacterium or blue green alga. Its trichomes are cylindrical arranged in unbranched form and the width ranges from 6 to 12 μm. The basic helical feature of its filaments is unique and can be found only in liquid culture medium. Spirulina has been so popular in the world due to its high nutritional contents. It has been used as protein and vitamin supplement to the health food industry, in aquaculture diets and fisheries. Cyanobacterium Spirulina is capable to grow in various kinds of culture media. Furthermore, decomposed organic and inorganic nutrients media have been proven to be good source of culture medium for Spirulina cultivation by many researchers. Among many strains, Spirulina platensis has been cultured in various waste organic matters to evaluate its growth and biochemical components under similar controlled culture conditions. The present investigation was carried out to formulate a low cost medium using cow dung ash for the biomass production of S. platensis. Different concentration gradients of cow dung ash medium i.e. 10-60% with standard medium were analyzed for Spirulina growth at pH 9.5 ± 2, temperature 28°C ± 2 and light intensity 3 Klux. Success of the experiment was found in 20% concentration level (1.212 g/l dry biomass) having 20% cow dung ash supplemented with 80% prescribed medium i.e. CFTRI medium. The maximum removal efficiency of 20% CDAM at the end of experiment was measured at 98.06%, 51%, 83.64% and 51.01% for TSS, TDS, COD and conductivity respectively. These results indicate the potentiality of cow dung ash to provide the nutrients to the culture medium that reduces its valuable cost and make it a cheaper and economic culture for S. platensis. The nutritional status of S. platensis cultured in 20% CDAM suggested that the biomass of Spirulina is nutritionally rich as per standard.