Unveiling the Use of Hydrophobic Eutectic Solutions as Task-Specific Solvents To Recover Bacterioruberin from Haloferax mediterranei

abstract

Haloarchaea make up a class of untapped marine microbial resources that constitute a promising source of valuable compounds with unique characteristics. Bacterioruberin is a C50 carotenoid produced by haloarchaea that possesses interesting antioxidant properties and bioactivities relevant to the food and cosmetic industries. As a substitute for the conventional organic solvents used in the extraction of nonpolar pigments, natural and biocompatible hydrophobic eutectic solvents (HES) based on the mixture of menthol with carboxylic acids were investigated for the extraction of bacterioruberin. Seven HES systems were screened both as neat solvents and in the presence of water. The menthol and levulinic acid mixture displayed a 4-fold improvement over both the ethanol control and the other HES, due to the dual action of its components. Additionally, the recovery of proteins could be achieved by the addition of water to the extract, resulting in a three-phase partition system and the formation of a protein-rich interfacial precipitate. The process intensification was assessed through the reuse of the eutectic phase over five successive extraction cycles, achieving a bacterioruberin-rich extract of 2.13 mg(bacterioruberin) mL(HES) (-1). Finally, the carbon footprint of the process was determined. The results highlight the potential of HES as biocompatible solvents for the recovery of value-added compounds from marine biomass, while the use of three-phase partition allows the recovery of proteins producing a second product stream.

keywords

IONIC LIQUIDS; PURIFICATION; CAROTENOIDS; EXTRACTION; STABILITY; TOXICITY; PROTEINS; MENTHOL; GREENER

subject category

Chemistry; Science & Technology - Other Topics; Engineering

authors

Kholany, M; Schaeffer, N; Macário, IPE; Veloso, T; Caetano, T; Pereira, JL; Dias, ACRV; Coutinho, JAP; Ventura, SPM

Groups

G4 - Renewable Materials and Circular Economy

Projects

CICECO - Aveiro Institute of Materials (UIDB/50011/2020)

CICECO - Aveiro Institute of Materials (UIDP/50011/2020)

Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)

acknowledgements

This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020, and LA/P/0006/2020, financed by national funds through the FCT/MEC (PIDDAC). The authors acknowledge FTC/ MCTES for the financial support to CESAM, UIDB/50017/2020 + UIDP/50017/2020 + LA/P/ 0094/2020, financed by national funds. The authors are also grateful to the FCT for the doctoral grants to M.K. (SFRH/ BD/138413/2018), I.P.E.M. (SFRH/BD/123850/2016), and T.V. (SFRH/BD/147346/2019). T.C. was funded by national funds (OE), through FCT, in the scope of the framework contract foreseen in the numbers 4, 5, and 6 of Article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/ 2017, of July (CEECIND/01463/2017). The National NMR Network, funded within the frame- work of the National Program for Scientific Re-equipment, contract REDE/1517/ RMN/2005 with funds from POCI 2010 (FEDER) and FCT, is also acknowledged.