Docosahexaenoic acid (DHA, C22:6) is an omega-3 fatty acid having beneficial health effects in human beings, though its production is severely hampered due to higher costs and lower yields from the synthesis. The current work concentrates on the intensification in the biomass production and DHA yield using Schizochytrium limacinum SR21. The effect of different media supplements on the DHA yields has been investigated. Citric acid which is a major intermediate in TCA (tricarboxylic acid) cycle proved better among different organic acids used in the work in terms of the yield of both biomass and DHA. The role of arginine and hydrophobic amino acids like tryptophan and tyrosine for the enhanced DHA production has also been illustrated. Monosaccharides (glucose and fructose) and glycerol also resulted in good cell growth and DHA yield. Maximum productivity of 5.7 g/l DHA has been obtained when glucose and glycerol were used simultaneously as carbon source. It has also been established that different steep liquors, tomato juice and sweet water can be used as possible cheaper substrates for the production of DHA from S. limacinum SR21. (C) 2015 Elsevier B.V. All rights reserved.