The present research work was carried out for assessing the optimum culture conditions for the biochemical constitution of spirulina platensis. Spirulina was cultured in conical flasks under three different concentration of rice mill effluent i.e (10 ml, 20 ml and 30 ml) under in in vitro conditions. After 30 days of inoculation of cultures were on the peak of growth and ready to harvest. Dried spirulina powder was subjected to biochemical analysis. The metabolites considered for biochemical analysis were protein, carbohydrate and chlorophyll. An excellent growth performance and maximum percentage of metabolites was observed in cultures those were kept under 20 ml of rice mill effluent containing culture medium. Optical density was considered growth parameter and so deliberated after the intervals of 5 days up till 30th days. The higher percentage of protein, carbohydrate and chlorophyll were recorded in 20 ml of rice mill effluent containing medium compare to other concentrations.
