Natural product separation and valorization

The production of target compounds from plants as renewable resources gains more and more interest. On the one hand the application of fossil resources might be partially replaced and, on the other hand, some particular complex molecules are only accessible via isolation from the natural plant origin. The projects in this frame are concerned with investigating the potential of crystallization processes for isolation of a certain target compound from plant-based extracts. Subjects currently studied refer to separation and purification of pharmaceutically relevant substances from the related plant extract (e.g. Artemisinin, Rutin or the Curcumin components) and the recovery and valorization of lignin with defined properties from lignocellulose within the biorefinery concept.

Separation of lignin from organic solvent pulping liquors and valorization via isolation of defined lignin molecular weight fractions

After developing the patented “LigniSep” process for separating well filterable lignin particles from organosolv black liquors in a batch, fedbatch and continuous precipitation process [1], the research activities were extended to the laboratory- to pilot-scale fractionation of lignocellulosic biomass using an acetone-based process in collaboration with partners from the European UNRAVEL project. Continuous lignin precipitation by solvent evaporation was conducted in a pilot-plant (500 L) at Fraunhofer CBP in Leuna adapted to the lab precipitation and solvent recovery conditions and successfully provided non-sticky, well processable lignin product at improved yields [2]. Further, we focused on valorization of the obtained lignin by solvent fractionation into various molecular weight fractions featuring different properties. At first, precipitation fractionation using water as antisolvent was applied to develop and evaluate a novel acetone/water-based SEC-MALS method for direct absolute molecular weight determination of lignin as a natural polydisperse system [3]. Afterwards, detailed studies on batch precipitation fractionation were performed, in particular verifying the effect of the lignin feed concentration on fractionation outcome, i.e. the molecular weight distribution of the obtained product fractions and their specific glass temperatures. Main results are shown in the Figure below revealing for the seven separated fractions a broad range of molecular weights between 2050 and 26500 g/mol comprising glass temperatures from 68 to 201°C [4]. Recent work was devoted to a novel lignin evaporation fractionation process (“LigniFrac”) that can be conducted in batch, fedbatch and continuous mode; a respective patent application has been filed [5].

[1]     Leschinsky, M., Unkelbach, G., Schulze, P., Lorenz, H., Seidel-Morgenstern, A.: Method for precipitating lignin from organosolv pulping liquors. EP3209829B1 (granted 21.9.2022), https://patents.google.com/patent/WO2016062676A1/en

[2]    Smit, A.T., Verges, M., Schulze, P., van Zomeren, A., Lorenz, H.: Laboratory- to pilot-scale fractionation of lignocellulosic biomass using an acetone organosolv process. ACS Sustainable Chem. Eng. 10 (2022), pp. 10503–10513

[3]    Ponnudurai, A., Schulze, P., Seidel-Morgenstern, A., Lorenz, H.: Fractionation and absolute molecular weight determination of organosolv lignin and its fractions: Analysis by a novel acetone-based SEC – MALS method. ACS Sustainable Chem. Eng. 11 (2023), pp. 766–776    

[4]    Ponnudurai, A., Schulze, P., Seidel-Morgenstern, A., Lorenz, H.: Effect of feed concentration in solvent/anti-solvent precipitation fractionation of lignin: Impact on lignins structure-property correlations. Sep. Pur. Technol. 33 (2024) 126343

[5]    Ponnudurai, A., Schulze, P., Seidel-Morgenstern, A., Lorenz, H.: Process for fractionationg polymeric material. Europäische Patentanmeldung Nr. 24 207 411.0 vom 18.10.2024

 

Further publications

Wünsche, S., Tenberg, V., Oliynyk, K., Seidel-Morgenstern, A., Lorenz, H., Sadeghi, M.: Experimental and model-based approach to evaluate solvent effects on the solubility of the pharmaceutical artemisinin. Eur. J. Pharm. Sci. 200 (2024) 106826

Wünsche, S., Seidel-Morgenstern. A., Lorenz, H.: Cocrystallization of curcuminoids with hydroxybenzenes pyrogallol and hydroxyquinol: Investigations of binary thermal phase behaviors. Cryst. Growth Des. 22 (2022), pp. 3303–3310

Minh Tan, N., Dinh Tien, V, Horosanskaia, E., Lorenz, H., Seidel-Morgenstern, A.: Method for purifying Rutin. VN10034540B (granted 1.12.2022)

Horosanskaia, E., Yuan, L., Seidel-Morgenstern, A., Lorenz, H.: Purification of Curcumin from Ternary Extract-Similar Mixtures of Curcuminoids in a Single Crystallization Step. Crystals 10 (2020), 206

Lorenz, H., Seidel-Morgenstern, A.: Separation processes to provide pure enantiomers and plant ingredients. Annu. Rev. Chem. Biomol. Eng. 11 (2020), pp. 469–502