Novel Organic Solvent Nanofiltration Approaches for Microbial Biosurfactants Downstream Processing
Glycolipid biosurfactants are the most prominent group of microbial biosurfactants, comprising rhamnolipids, sophorolipids and mannosylerythritol lipids (MELs). Usually, large amounts of hydrophobic substrates (e.g., vegetable oils) are used to achieve high titers (~200 g/L) of a crude product of lo...
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MDPI AG
2023-01-01
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| Series: | Membranes |
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| Online Access: | https://www.mdpi.com/2077-0375/13/1/81 |
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| author | Miguel Figueiredo Nascimento Petar Keković Isabel A. C. Ribeiro Nuno Torres Faria Frederico Castelo Ferreira |
| author_facet | Miguel Figueiredo Nascimento Petar Keković Isabel A. C. Ribeiro Nuno Torres Faria Frederico Castelo Ferreira |
| author_sort | Miguel Figueiredo Nascimento |
| collection | DOAJ |
| description | Glycolipid biosurfactants are the most prominent group of microbial biosurfactants, comprising rhamnolipids, sophorolipids and mannosylerythritol lipids (MELs). Usually, large amounts of hydrophobic substrates (e.g., vegetable oils) are used to achieve high titers (~200 g/L) of a crude product of low purity at values limited to 50–60%, contaminated with unconsumed triacylglycerol and residual free fatty acids and monoacylglycerides. The methods reported for the removal of these contaminants use a mixture of organic solvents, compromising solvent recyclability and increasing final process costs. This study reports, for the first time, an innovative downstream method for MELs, in which 90% of the triacylglycerols are separated from the crude MEL mixture in a first stage and the other lipid derivatives (free fatty acids, mono- and diacylglycerols) are removed by organic solvent nanofiltration (OSN). Three commercially available membranes (GMT-oNF-2, PuraMEm-600 and DuramMem-500) and several homemade membranes, casted from 22, 24 or 26% (<i>w/v</i>) polybenzimidazole (PBI) solutions, were assessed for crude MELs purification by diafiltration. A final purity of 87–90% in the MELs was obtained by filtering two diavolumes of methanol or ethyl acetate solutions through a PBI 26% membrane, resulting in MELs losses of 14.7 ± 6.1% and 15.3 ± 2.2%, respectively. Higher biosurfactant purities can be archived using the PBI 26% membrane at higher DV, but at the cost of higher product losses. Namely, in MeOH, the use of 6 DV leads to losses of 32% for MELs and 18% for sophorolipids. To obtain MELs at reagent grade with purities equal or higher than 97%, a two-sequential cascade filtration approach was implemented using the commercial membrane, GMT-oNF. In such a process, MELs with 98% purity was obtained at the cost of 11.6% MELs losses. Finally, decoloration, important in some applications, was successfully assessed using activated carbon. Overall, this study reports a unique solution for microbial biosurfactants production with minimal product losses, enabling solvent recycling and potentially reducing costs. |
| first_indexed | 2024-03-09T11:44:04Z |
| format | Article |
| id | doaj.art-fad4a8cb68ce4dcba8a2e3ded9d61534 |
| institution | Directory Open Access Journal |
| issn | 2077-0375 |
| language | English |
| last_indexed | 2024-03-09T11:44:04Z |
| publishDate | 2023-01-01 |
| publisher | MDPI AG |
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| series | Membranes |
| spelling | doaj.art-fad4a8cb68ce4dcba8a2e3ded9d615342023-11-30T23:26:57ZengMDPI AGMembranes2077-03752023-01-011318110.3390/membranes13010081Novel Organic Solvent Nanofiltration Approaches for Microbial Biosurfactants Downstream ProcessingMiguel Figueiredo Nascimento0Petar Keković1Isabel A. C. Ribeiro2Nuno Torres Faria3Frederico Castelo Ferreira4Department of Bioengineering, iBB—Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, PortugalDepartment of Bioengineering, iBB—Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, PortugalResearch Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, PortugalDepartment of Bioengineering, iBB—Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, PortugalDepartment of Bioengineering, iBB—Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, PortugalGlycolipid biosurfactants are the most prominent group of microbial biosurfactants, comprising rhamnolipids, sophorolipids and mannosylerythritol lipids (MELs). Usually, large amounts of hydrophobic substrates (e.g., vegetable oils) are used to achieve high titers (~200 g/L) of a crude product of low purity at values limited to 50–60%, contaminated with unconsumed triacylglycerol and residual free fatty acids and monoacylglycerides. The methods reported for the removal of these contaminants use a mixture of organic solvents, compromising solvent recyclability and increasing final process costs. This study reports, for the first time, an innovative downstream method for MELs, in which 90% of the triacylglycerols are separated from the crude MEL mixture in a first stage and the other lipid derivatives (free fatty acids, mono- and diacylglycerols) are removed by organic solvent nanofiltration (OSN). Three commercially available membranes (GMT-oNF-2, PuraMEm-600 and DuramMem-500) and several homemade membranes, casted from 22, 24 or 26% (<i>w/v</i>) polybenzimidazole (PBI) solutions, were assessed for crude MELs purification by diafiltration. A final purity of 87–90% in the MELs was obtained by filtering two diavolumes of methanol or ethyl acetate solutions through a PBI 26% membrane, resulting in MELs losses of 14.7 ± 6.1% and 15.3 ± 2.2%, respectively. Higher biosurfactant purities can be archived using the PBI 26% membrane at higher DV, but at the cost of higher product losses. Namely, in MeOH, the use of 6 DV leads to losses of 32% for MELs and 18% for sophorolipids. To obtain MELs at reagent grade with purities equal or higher than 97%, a two-sequential cascade filtration approach was implemented using the commercial membrane, GMT-oNF. In such a process, MELs with 98% purity was obtained at the cost of 11.6% MELs losses. Finally, decoloration, important in some applications, was successfully assessed using activated carbon. Overall, this study reports a unique solution for microbial biosurfactants production with minimal product losses, enabling solvent recycling and potentially reducing costs.https://www.mdpi.com/2077-0375/13/1/81downstream processingmicrobial biosurfactantsmannosylerythritol lipidsnanofiltration technologyactivated carbon |
| spellingShingle | Miguel Figueiredo Nascimento Petar Keković Isabel A. C. Ribeiro Nuno Torres Faria Frederico Castelo Ferreira Novel Organic Solvent Nanofiltration Approaches for Microbial Biosurfactants Downstream Processing Membranes downstream processing microbial biosurfactants mannosylerythritol lipids nanofiltration technology activated carbon |
| title | Novel Organic Solvent Nanofiltration Approaches for Microbial Biosurfactants Downstream Processing |
| title_full | Novel Organic Solvent Nanofiltration Approaches for Microbial Biosurfactants Downstream Processing |
| title_fullStr | Novel Organic Solvent Nanofiltration Approaches for Microbial Biosurfactants Downstream Processing |
| title_full_unstemmed | Novel Organic Solvent Nanofiltration Approaches for Microbial Biosurfactants Downstream Processing |
| title_short | Novel Organic Solvent Nanofiltration Approaches for Microbial Biosurfactants Downstream Processing |
| title_sort | novel organic solvent nanofiltration approaches for microbial biosurfactants downstream processing |
| topic | downstream processing microbial biosurfactants mannosylerythritol lipids nanofiltration technology activated carbon |
| url | https://www.mdpi.com/2077-0375/13/1/81 |
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