Calorific values of C hlorella vulgaris ( T rebouxiophyceae) as a function of different phosphorus concentrations

Summary Quantification of the calorific content of microalgae is critical in studies of energy flow, trophic partitioning, plant/herbivore interactions in aquaculture and biomass production for biofuels. We investigated the calorific value and biochemical composition of C hlorella vulgaris at different phosphorus ( P ) concentrations (6.0 × 10 −7 , 2.3 × 10 −6 and 2.3 × 10 −4  mol L −1 P ). As expected, the control (2.3 × 10 −4  mol L −1 P ) supported better growth than P limited treatments. Biomolecules like total carbohydrates and lipids accumulated under P limitation, which significantly correlated with high calorific values. Lipid class composition showed that triacylglycerols were the most accumulated under P limited conditions. The calorific value reported under control conditions (13.78 kJ g −1 ) was less than those obtained under P limitation (30.47–33.07 kJ g −1 ). The highest calorific value with less growth retardation was obtained at 2.3 × 10 −6  mol L −1 P .