1 Introduction
2 Salting-out extraction
Tab.1 Some applications of SOE |
Type | Extractant/salting-out agent | Target products | Ref. |
---|---|---|---|
1 | Polyethylene glycol (4000)/potassium phosphate | Cphycocyanin | [37] |
2 | Ethanol/dipotassium hydrogen phosphate (K2HPO4) Acetone/K2HPO4 | Lactic acid Acetoin | [38] [39] |
3 | Pentanol/sodium phosphate | 1,3-Propanediol | [40] |
4 | 1-Butyl-3-methylimidazolium chloride/K2HPO4 | Testosterone and epitestosterone | [41] |
Fig.1 Flow chart and mechanism of salting-out/sugaring-out extraction. (a) fermentation broth/aqueous solution containing target product(s) and impurities; (b) add salt(s)/sugar(s) and extractant(s) to fermentation broth/aqueous solution; (c) the attractive effect of extractant(s) impel the target product(s) to move toward extractant(s), meanwhile, the repulsive interaction between salt(s)/sugar(s) and target product(s) drives target product(s) to move away from fermentation broth/aqueous solution; (d) due to the changes in solubility of different solvents, the whole system will form two phase gradually; and the target product(s) will move to the upper phase (organic phase) with extractant(s) while the salt(s) and most of impurities will move to the bottom phase (aqueous phase); (e) phase splitting, target product(s) will be obtained by a series of separation operations from upper phase. |
2.1 SOE of biofuels
Tab.2 SOE of biobutanol from simulated fermentation broths or real fermentation broths |
SOE systems | Type of fermentation broth | Partition coefficient | Recovery | Removal | Ref. | |
---|---|---|---|---|---|---|
Cells | Proteins | |||||
Cyclopentanol, n-pentaldehyde, tertiary pentanol, and ADOL85NF+ CaCl2, KCl, NaCl, CH3COOK, CH3COONa | Simulated ABE fermentation broth | – | – | – | – | [43] |
41.7% Acetone+ 25% Na2CO3 | Simulated ABE fermentation broth | 55.71 | 98.38% | – | – | [44] |
39.6% Ethanol+ 25% Na2CO3 | Simulated ABE fermentation broth | 35.06 | 97.87% | – | – | [44] |
33% Acetone+ 30% Na2CO3 | Unfiltered ABE fermentation broth | 32.17 | 95.99% | 99.92% | 87.13% | [44] |
47.5% Ethanol+ 50% K2HPO4 | Simulated ABE fermentation broth | 25.03 | 96.87% | – | – | [44] |
40% Acetone+ 60% K2HPO4 | Unfiltered ABE fermentation broth | – | ~100% | 99.86% | 91.21% | [44] |
17.51% Acetone+ 21.44% K2HPO4 | ABE fermentation broth | 63.13 | 98.10% | 99.12% | 95.71% | [45] |
2-Ethyl-1-hexanol/cyclopentanol/2-methyl-2-butanol+ K4P2O7 | Simulated isobutanol fermentation broth | – | ~100% | – | – | [47] |
2-Ethyl-1-hexanol/cyclopentanol/2-methyl-2-butanol+ K2HPO4 | Simulated isobutanol fermentation broth | – | ~100% | – | – | [47] |
2-Ethyl-1-hexanol/cyclopentanol/2-methyl-2-butanol+ K3PO4 | Simulated isobutanol fermentation broth | – | ~100% | – | – | [47] |
2-Ethyl-1-hexanol/cyclopentanol/2-methyl-2-butanol+ K2CO3 | Simulated isobutanol fermentation broth | – | ~100% | – | – | [47] |
2.2 SOE of bio-based chemicals
Tab.3 SOE of bio-based chemicals |
Target products | SOE systems | Partition coefficient | Recovery | Removal | Ref. | |
---|---|---|---|---|---|---|
Cells | Proteins | |||||
1,3-Propanediol | 46% Ethanol+ (NH4)2SO4 (saturated) | 4.77 | 93.7% | 99.7% | 79.0% | [25] |
35% Methanol+ K2HPO4 (saturated) | 38.3 | 98.1% | 99.85% | 92.4% | [29] | |
Ethanol+ 37.5% K2HPO4 | 10.86 | 90.30% | – | – | [52] | |
28% Ethanol+ 34% K3PO4 | 33 | 97% | – | – | [53] | |
Pentanol+ 0.4 g∙L–1 Na3PO4 | 3.72 | 72% | – | – | [40] | |
Pentanol+ 0.4 g∙L–1 Na2SO4 | 2.52 | 65.6% | – | – | [40] | |
Ethanol+ Na2CO3 | – | 97.9% | 99.1% | 81.9% | [54] | |
1) 30% Isopropanol+ 30% K2CO3 2) 28% Ethanol | 9.81 | 92.4% | 100% | 98.5% | [55] | |
2,3-Butanediol | 24% Ethanol+ 25% K2HPO4 | 28.34 | 98.13% | 99.63% | 85.9% | [26] |
21% Ethanol+ 17% K2HPO4 | 13.4 | 99% | – | 89% | [60] | |
32% Ethanol+ 16% (NH4)2SO4 | 7.1 | 91.7 | 99.7% | 91.2% | [72] | |
2-sec-Butyl phenol+ 10 wt-% K2HPO4 | 3.04 | – | – | – | [58] | |
1-Butanol+ 10 wt-% K2HPO4 | 2.41 | – | – | – | [58] | |
1-Butanol+ 10 wt-% K2HPO4 | 2.26 | – | – | – | [36] | |
34% (w/w) 2-Propanol and 20% (w/w) (NH4)2SO4 | 9.9 | 93.7% | 99% | 85% | [61] | |
Tetrahydrofurn+ K2CO3 | – | 92.2% | – | – | [59] | |
Acetoin | Ethyl acetate+ K2HPO4 (v/v= 2:1) | 5.47 | 91.3% | – | – | [64] |
100 mL Ethyl acetate+ 20% ethanol+ 50% K2HPO4 | 18.5 | 95.3% | – | – | [64] | |
40% 1-Propanol+ K4P2O7 (saturated) | – | ~100% | – | – | [65] | |
6% EOAB+ 38% K3PO4 | 40.54 | 92.7% | – | – | [66] | |
Lactic acid | 30.23% Ethanol+ 18.40% K2HPO4 | 2.26 | 87% | – | – | [38] |
30% Ethanol+ 14% K2HPO4 | 3.23 | 90.6% | 100% | 85.9% | [69] | |
26% Methanol+ 25% K2HPO4 | 4.01 | 86% | 100% | 85.9% | [69] | |
28% Ethanol+ 30% K2CO3 | 1.27 | 73.8% | 100% | 98.5% | [55] | |
Succinic acid | 30% Acetone+ 20% (NH4)2SO4 | 8.64 | 90.05% | 99.03% | 90.82% | [70] |
Butyric acid | 26.7% Ethanol+ 20% NaH2PO4 | 106.2 | 99.5% | – | – | [71] |
3 Salting-out
Tab.4 Some applications of salting-out |
System | Target products | Ref. |
---|---|---|
Acetonitrile+ H2O+ LiCl, + NaCl, + KCl Acetone+ H2O+ NaCl 2-Propanol+ H2O+ NaCl | Acetonitrile Acetone 2-Propanol | [79] |
1-Methyl-2-pyrrolidone+ Na2CO3 + H2O 1-Methyl-2-pyrrolidone+ K2CO3 + H2O Acetonitrile+ Na2CO3 + H2O Acetonitrile+ K2CO3 + H2O | 1-Methyl-2-pyrrolidone Acetonitrile | [80] |
H2O+ ethanol+ acetone+ NaCl | Ethanol+ acetone | [81] |
2,3-Butanediol+ H2O+ K2CO3 | 2,3-Butanediol | [82] |
NaCl+ H2O+ acetone, acetonitrile, 1,4-dioxane, tetrahydrofuran, 1-propanol, or 2-propanol | Acetone, acetonitrile, 1,4-dioxane, tetrahydrofuran, 1-propanol, or 2-propanol | [83] |
Fig.2 Flow chart and mechanism of salting-out/sugaring-out. (a) fermentation broth/aqueous solution containing target product(s) and impurities; (b) add salt(s)/sugar(s) to fermentation broth/aqueous solution; (c) the repulsive interaction between salt(s)/sugar(s) and target product(s) drives target product(s) to move away from fermentation broth/aqueous solution; (d) due to the changes in solubility of different solvents, the whole system will form two phase gradually; and the target product(s) will move to the upper phase (organic phase) because of its(their) low density, while the salt(s) and most of impurities will move to the bottom phase (water phase); (e) phase splitting; target product(s) will be obtained by decanting the upper phase. |
3.1 Salting-out of biofuels
Tab.5 Salting-out of biofuel |
Type of ABE fermentation broth | Type of salts | Water content of the organic phase | Recovery/% | Ref. | ||
---|---|---|---|---|---|---|
Acetone | Butanol | Ethanol | ||||
Concentrated a) | K2CO3 | 6.83% | 99 | 98.3 | 98 | [84] |
Concentrated a) | K2HPO4 | 5.50% | ~100 | ~100 | ~100 | [91] |
Concentrated a) | K3PO4 | 7.11% | ~100 | ~100 | ~100 | [92] |
Concentrated a) | K4P2O7 | 5.21% | ~100 | ~100 | ~100 | [93] |
Dilute model solution b) | K2CO3 | 5.59% | 70.2 | 93.7 | 60.8 | [94] |
Dilute model solution b) | K2HPO4 | 10.38% | 96.1 | 100 | 85.6 | [94] |
Dilute model solution b) | K3PO4 | 7.19% | 89.4 | 100 | 72.2 | [95] |
Dilute c) | K3PO4 | 7.0% | 72.9 | 100 | 42.1 | [95] |
Dilute model solution b) | K4P2O7 | 7.76% | 84.1 | 100 | 55.9 | [96] |
a) Concentrated ABE fermentation broth: ethanol, 4 wt-%; acetone, 26%; 1-butanol, 10%; others, water; b) model solution: ethanol, 0.18 wt-%; acetone, 0.54%;1-butanol, 1.08%; others, water; c) real fermentation broth: the concentration of acetone, 1-butanol and ethanol were 0.39, 1.00 and 0.04 wt-%, respectively. |
3.2 Salting-out of bio-based chemicals
Tab.6 Salting-out of bio-based chemicals |
Target products | Salts | Partition coefficient | Recovery/% | Water content of the organic phase/% | Ref. |
---|---|---|---|---|---|
1,3-Propanediol | |||||
150 g∙L–1 | 50% K2CO3 | 22.6 | – | 20.5 | [100] |
150 g∙L–1 | 50% K3PO4 | 65.1 | – | 28.3 | [100] |
150 g∙L–1 | 55% K4P2O7 | 300.9 | 95.7 | 17.3 | [100] |
2,3-Butanediol | |||||
50 g∙L–1 | 50% K2HPO4 | – | 67.8 | 30.6 | [59] |
50 g∙L–1 | 50% K3PO4 | – | 54.5 | 18.2 | [59] |
50 g∙L–1 | 50% K2CO3 | – | 44.9 | 16.6 | [59] |
50 g∙L–1 | 50% KF | – | 36.0 | 23.8 | [59] |
100 g∙L–1 | 50% K2CO3 | 236.6 | 94.9 | 15.72 | [27] |
100 g∙L–1 | 50% K3PO4 | 723.6 | 97.5 | 22.5 | [27] |
100 g∙L–1 | 50% K2HPO4 | 277.6 | 93.7 | 31.1 | [27] |
100 g∙L–1 | 50% K4P2O7 | 1791.1 | 99.0 | 19.0 | [27] |
100 g∙L–1 | 50.79% K2CO3 | 313 | 96.28 | – | [101] |
99.8 g∙L–1 a) | 67.9% K2CO3 | – | 94.6 | – | [101] |
a) The real fermentation from saccharified starch contained 99.8 g∙L–1 2,3-butanediol, 1.7 g∙L–1 acetoin and 4.3 g∙L–1 ethanol. |
4 Sugaring-out extraction
Tab.7 Sugaring-out extraction of bio-based chemicals |
Target products | Sugaring-out extraction systems | Type of fermentation broth | Partition coefficient | Recovery | References |
---|---|---|---|---|---|
Succinic acid | 27% Glucose+ 40% t-butanol | Synthetic fermentation broth | 5.14 | 88.15% | [33] |
27% Glucose+ 40% t-butanol+ 9% (NH4)2SO4 | Synthetic fermentation broth | – | 89.55% | [33] | |
30% Glucose+ 45% [Bmim]BF4 | Simulated fermentation broth | 2.53 | 75.96% | [110] | |
30% Glucose+ 45% [Bmim]BF4 | Filtered fermentation broth | – | 73.71% | [110] | |
30% Glucose+ 45% [Bmim]BF4 | Unfiltered fermentation broth | – | 72.53% | [110] | |
Lactic aicd | 12% Glucose+ 40% isopropanol | Simulated fermentation broth | 1.39 | 84.27% | [112] |
2,3-butanediol | 30% Glucose+ 1.8% (NH4)2HPO4 + 100% t-butanol | Filtered fermentation broth | – | 75.6% | [113] |
Acetoin | Glucose+ ethyl acetate (v/v= 1:2) | Unfiltered fermentation broth | – | 61.2% | [114] |
5 Sugaring-out
Tab.8 Sugaring-out of fuels and chemicals |
Target products | Type of sugar | Type of system | Initial concentration of sugars | Concentration of target products | References |
---|---|---|---|---|---|
Butanol | Sucrose | Concentrated ABE system | 650 g∙kg–1 | 64.52% | [34] |
Glucose | Concentrated ABE system | 500 g∙kg–1 | 62.62% | [34] | |
Ethanol | Sucrose | Concentrated ABE system | 650 g∙kg–1 | 5.60% | [34] |
Glucose | Concentrated ABE system | 500 g∙kg–1 | 5.61% | [34] | |
Acetone | Sucrose | Concentrated ABE system | 650 g∙kg–1 | 15.57% | [34] |
Glucose | Concentrated ABE system | 500 g∙kg–1 | 15.05% | [34] | |
Acetonitrile | Glucose | Acetonitrile aqueous solution | 50 g∙L–1 | 95.4% | [119] |
Xylose | Acetonitrile aqueous solution | 50 g∙L–1 | 90.9% | [119] | |
Arabinose | Acetonitrile aqueous solution | 40 g∙L–1 | 94.9% | [119] | |
Fructose | Acetonitrile aqueous solution | 50 g∙L–1 | 89.1% | [119] | |
Sucrose | Acetonitrile aqueous solution | 50 g∙L–1 | 90.4% | [119] |