Simultaneous extraction of chlorophylls, proteins, and carbohydrates from isolated Chlorella thermophila using a triphasic separation technique: A biorefinery approach

Abstract The separation of multiple products from microalgae using a biorefinery approach is essential for the economic sustainability of microalgae‐based products. In the current study, a technique for the simultaneous extraction of such products was investigated for the complete valorization of microalgae biomass. Three principal metabolites – chlorophylls, carbohydrates and proteins – were simultaneously fractionated from the biomass of isolated Chlorella thermophila using a modified version of the triphasic separation (TPS) process. Optimized process parameters were determined as: (i) ammonium sulfate as the salt; (ii) 40% (w/v) as the salt concentration; (iii) 1:1 as the salt/alcohol ratio; (iv) 0.25% (w/w) as biomass loading; (v) 6 min of homogenization time, and (vi) 10 000 rpm as homogenization speed. These optimized process parameters resulted in the simultaneous recovery of 71%, 40%, and 22% yields for proteins, carbohydrates, and chlorophylls, respectively. Ultrastructure analysis revealed that intracellular metabolites could be extracted without complete cell disruption. Finally, a comparative analysis between triphasic separation with and without homogenization demonstrated the economic feasibility of the optimized extraction process.