Recovery of soluble proteins from Chlorella vulgaris by bead-milling and microfiltration: Impact of the concentration and the physicochemical conditions during the cell disruption on the whole process

Chlorella vulgaris proteins show high potential for food applications. The challenge of biorefinery is to choose the best processes coupling which can ensure the integrity of the molecules and limit energy consumption. This study aimed at understanding the impact of biomass concentration and physicochemical conditions during cell disruption, on the whole process (bead milling (BM), centrifugation, microfiltration). The best scenario tested (BM: 60 g/LDW, 10 degrees C, lysate dilution: 30 g/LDW, pH 7, 20 degrees C before centrifugation and filtration of the supernatant at a volume reduction ratio VRR = 3) allowed a soluble protein recovery eta S = 12 % with a limited energy consumption of 10 kW h/g protein. Coupling BM at 90 g/LDW, pH 7, a dilution at 20 degrees C, with NaCl 0.1 M at 30 g/ LDW and filtration at VRR = 20 would lead to eta S>25 %. The final soluble proteins contained no green pigment; their purity increased from 5 % in the raw biomass to 22 % in the permeate.

Automated summary

The study aimed to investigate the impact of different biorefinery processes on Chlorella vulgaris proteins, and found that under certain conditions, a higher protein recovery could be achieved. Proper bead milling conditions and dilution concentration contribute to the increase of protein purity.