Fractionation of Isochrysis galbana Proteins, Arabinans, and Glucans Using Ionic-Liquid-Based Aqueous Biphasic Systems

Abstract

Isochrysis galbana (I. galbana) is a microalgae species rich in biomolecules of high commercial value and industrial relevance. Despite the numerous studies done on the extraction of different compounds from microalgae, the complete valorization of the biomass under the biorefinery concept is scarce or even inexistent. The mixture of different compounds found in the different extracts obtained from the microalgae biomass is one of the most important drawbacks in the field. Despite the large interest of academia and industry in the different classes of bioactive compounds composing microalgae, these are still poorly explored due to the low efficiency of the downstream processes used up to date. In this context, this work proposes the development of an efficient purification process by applying ionic liquid (IL)-based aqueous biphasic systems (ABS) to separate proteins from arabinose- and glucose-rich polysaccharides. For this purpose, the nature of the inorganic salt, the IL structural features (anion and alkyl chain length) and the extraction point (using different inorganic salt concentrations) were the conditions optimized. After the proper selection of the most performant IL-ABS (%EEcarb = 71.21 ± 5.21% to the bottom phase and %EEprot = 100% to the top phase), a complete downstream process was developed and implemented, in which the isolation of the target biomolecules (proteins, arabinose- and glucose-rich polysaccharides) and the reuse of the phase formers and main solvents applied was considered. In summary, the approach proposed using IL-ABS appears as a simple and efficient method of purification easily integrated into continuous flow processes, thus demonstrating its industrial potential.

Sustainable liquid supports for laccase immobilization and reuse: Degradation of dyes in aqueous biphasic systems

“…Compared to polymer-based ABS, IL-rich systems show a set of important advantages, such as low viscosity, fast phase separation, and high extraction efficiency and selectivity achieved by the proper tailoring of the IL chemical structure (Ferreira et al, 2014;Freire et al, 2012). Furthermore, ILs, if properly selected, lead to improved activity and stability of a wide number of enzymes and improved selectivity in biocatalysis (Bisht et al, 2017;Capela et al, 2020;Dossantos et al, 2018;Santos et al, 2018;Schindl et al, 2019).…”

Multiproduct Microalgae Biorefineries Mediated by Ionic Liquids

“…With the plethora of available ILs (Box 1), it is possible to develop extraction methods tailored for specific microalgae products. In the past years, ILs have attracted considerable attention as medium for catalysis [17][18][19][20] in extraction and separation processes [21][22][23][24], and for the dissolution of biomaterials [25].…”

“…This ability of IL-based ABSs holds a huge prospect in extracting fragile biomolecules from raw materials such as microalgae, which contain molecules of different polarity and solubility (proteins, pigments, lipids, and carbohydrates). Beyond one study [24] that used harsh extraction conditions, only a few studies reported the separation of multiple (fragile) microalgae biomolecules using IL-based ABSs under mild conditions…”

Computer-aided solvent screening for the fractionation of wet microalgae biomass

“…Several methods are currently researched for that purpose, such as supercritical fluid extraction, aqueous two phase systems , membrane separation, threephase partitioning and pressurized liquid extraction. [31][32][33][34][35] In addition to purely solvent-based methods, also the cell disruption step can be exploited for biomass fractionation. Alavieh et al focused on a cell-disruption strategy using bead beating and enzymatic lysis to separate lipids from carbohydrates and proteins of Chlorella vulgaris.…”