Table 7.
The efficiency of downstream methods (LLE—liquid–liquid extraction; CR—crystallization, CP—column purification), indicating the solvent used, the amount of solvent required (volume of solvent/volume of fermentation broth), easiness to recycle solvent used (Y—for easy, N—for difficult), number of solvent shifts, percentage of recovery and final purity (%). A “/” is used to separate information from different unit operations within the same process. “NA” indicates omitted information in the source. At grey are the results obtained here in this study.
| Glycolipid | Method | Solvent Used |
Solvent Required (Solvent Volume/Broth Volume) | Solvent Recyclability Easiness |
No. of Solvent Shifts | Recovery (% w/w) |
Final Purity (% w/w) |
Comments | Ref. |
|---|---|---|---|---|---|---|---|---|---|
| RLs | LLE | EtOAc | 4:1 | Y | 1 | 65.5 | 84.1 | Acid precipitation using HCl, followed by Ethyl acetate LLE | [47] |
| LLE + CP | EtOAc | 2:1/NA * | N | 3 | 89.4 | 90.7 | LLE with n-hexane, followed by extraction with ethyl acetate. * Solvents used in various ratios for column purification |
[48] | |
| n-hexane | 3:1/NA * | N | |||||||
| SLs | LLE + CP | EtOAc | 0.8:1/NA * | N | 2 | NA ** | NA ** | * Column chromatography used for purification, solvent consumption not reported ** Recovery rate and final purity not reported |
[49] |
| 2-propanol | 0.2:1 | N | |||||||
| MeOH | NA * | N | |||||||
| LLE + CP | EtOAc | 0.8:1/NA * | N | 3 | NA ** | NA ** | Oleic acid used as lipophylic substrate LLE with Ethyl acetate/2-propanol mixture, extract washing with hexane, followed by column chromatography * Solvent consumed for column purification not reported ** Recovery rate and final purity not reported |
[50] | |
| 2-propanol | 0.2:1 | N | |||||||
| n-hexane | 1:1 | Y | |||||||
| Chloroform | NA * | N | |||||||
| MeOH | NA * | N | |||||||
| MELs | LLE | MTBE | 3:1 | Y | 3 | 8 | 100 | Multiple solvents used in subsequent extractions | [25] |
| MeOH | 1.6:1 | N | |||||||
| Cyclohexane | 3:1 | N | |||||||
| n-hexane | 1:1 | N | |||||||
| LLE + CP Preparative HPLC |
EtOAc | 2:1 | Y | 3 | 4 ** | 100 | * Two column separations and preparative HPLC using CHCl4/MeOH ratios 90/10, 95/5, 96/4. Unknown volumes, non-recyclable ** Reported recovery based on mass of MELs after L–L extraction |
[22] | |
| MeOH | 1:1/ NA * | Y; N * | |||||||
| Chloroform | NA * | N * | |||||||
| LLE + CP | EtOAc | 1:1 | Y | 2 | 50 ** | 100 | * Column purification with gradient elution by CHCl4/Acetone mixture (80:20, 40:60 and 0:100, v/v). Volume unknown, most likely immense, non-recyclable ** Reported recovery based on mass of MELs after L-L extraction |
[23] | |
| Chloroform | NA * | N | |||||||
| Acetone | NA * | N | |||||||
| LLE | MeOH | 2.5:1 | N | 1 | 90 | 100 | Multiple solvents used in subsequent extractions; solvent shifts avoided | [26] | |
| n-hexane | 3:1 | N | |||||||
| LLE + OSN + AC treatment |
EtOAc | 21 | Y | 0 | 88.4 | 98.8 | Method reported in this article. No TAG present. EtOAc used through all the process. Cascade system (4 DV + 4 DV), GMT-oNF-2 membrane. 90% of solvent recycled |
||
| LLE + TAG removal + OSN + AC treatment |
EtOAc + MeOH | 1:1 | Y | 1 | 64.8 | 97.1 | Method reported in this article. TAG present. EtOAc used in extraction. MeOH used through the other steps of the process. Single diafiltration (6 DV), PBI 26% membrane. 90% of solvent recycled | ||