A variety of non-functionalized Brönsted-acidic ionic liquids "BAILs" HNMP-HSO4, HNMP-H2PO4, HNMP-Cl, and choline chloride (ChCl)-based deep eutectic solvents (DESs), specifcally choline chloride-oxalic acid (ChCl-OxA) and choline
chloride-urea (ChCl-Urea), were used as efcient solvents for the extraction of lipids." from Dunaliella salina. The acidity order of these BAILs was evaluated using the Hammett acidity scale H0 and pKa values measurement and the results
showed a good agreement between the observed Brönsted acidity activity sequence in the lipid extraction yields and the
Hammett acidity order determined from UV–visible spectroscopy of BAILs. HNMP-HSO4 showed the highest acidity level
(H0 (CH2Cl2)=0.58, H0 (H2O)=1.51, pKa=1.38). The best lipid extraction yields (32±1) were obtained using the deep
eutectic solvent ChCl-Urea and HNMP-HSO4 ionic liquids after 24 h, compared to the results from Bligh and Dyer extraction. The total lipid yields of ionic liquids were signifcantly diferent at 2 h and 24 h treatment duration (HNMP-HSO4,
total lipid yields 2 h=28, 24 h=32) however, no signifcant diferences were observed in the lipid extraction yields of DESs
(ChCl-Urea, total lipid yields 2 h=34 wt%, 24 h=32 wt%). The oils extracted with ionic liquids (ILs) and deep eutectic
solvents (DESs) exhibited lower chlorophyll impurities. After 24 h of treatment with HNMP-HSO4, HNMP-H2PO4, HNMPCl, ChCl-Urea, and ChCl-OxA, the chlorophyll residues measured were 0.007, 0.009, 0.010, 0.10, 0.01, and 0.09 μg mg−1
of lipid, respectively. These fndings highlight the potential of BAILs and DESs as efective and environmentally friendly
solvents for enhancing lipid extraction from microalgae, with signifcant implications for the production of biofuels and
other lipid-based products