Partial deproteinization of starved Parachlorella kessleri using bio-based ionic liquids: a comparative study of direct contact and microwave-assisted extraction
Year: 2026
Type: article
Abstract: This study evaluated the partial protein extraction from nitrogen-deficient Parachlorella kessleri using four ionic liquids (choline chloride, choline acetate, choline urea, and guanidinium iodide) and two extraction methods: direct contact and microwave-assisted extraction. Dry biomass (0.5 g, dry weight basis) was mixed with ionic liquids at a 1:2 w/w biomass-to-IL ratio at 50 °C for 90 min. No mechanical cell disruption was applied before extraction. A two-way factorial design was used to evaluate the effects of ionic liquid type, extraction method, and their interaction on the extraction efficiency of proteins, carbohydrates, and lipids. Data were analysed using two-way ANOVA. Protein extraction efficiency ranged from 6.1% to 13.8% across all conditions. Choline acetate achieved the highest protein extraction efficiency (11.4 ± 0.3% with direct contact and 13.8 ± 1.1% with microwave-assisted extraction), outperforming the other ionic liquids (p < 0.001). The superior performance of choline acetate, compared to choline chloride (8.5% in both cases) and choline urea (11.1–11.9%), may be related to the higher hydrogen-bonding basicity of the acetate anion, although other properties of the ionic liquids were not evaluated. Mass balance analysis, based on complete characterization of the aqueous, organic, and solid phases, demonstrated acceptable biomass recovery ranging from 91.9% to 103.5%. The solid residue contained 47–54% carbohydrates, 18–27% lipids, 22–27% protein, and 2–6% ash (dry weight basis), indicating that the phase characterization gave a reliable mass balance. The low deproteinization efficiencies may be linked to the rigid cell wall of the starved microalga, which was not disrupted before extraction. They show the need for improved protein removal strategies.
Source: Biomass and Bioenergy
Institution: Universitat Rovira i Virgili
Language: English
Field: Energy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,270
Funder: Universitat Rovira i Virgili
OpenAlex ID: W7224965293