Natural deep eutectic solvent as a unique solvent for valorisation of orange peel waste by the integrated biorefinery approach

• Published in: Waste management (Elmsford) Vol. 120; pp. 340 - 350
• Main Authors: Panić, Manuela, Andlar, Martina, Tišma, Marina, Rezić, Tonči, Šibalić, Darijo, Cvjetko Bubalo, Marina, Radojčić Redovniković, Ivana
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 01.02.2021
• Subjects: (R)-1-phenylethanol; Biorefinery; Citrus sinensis; D-limonene; Hydrolysis; Lignin; Natural deep eutectic solvents; Orange peel waste; Pectin methylestrase; Polyphenols; Solvents; SWOT analysis; CGlc; HBA; AV15; Orange peel waste; HBD; AV30; Natural deep eutectic solvents; Pectin methylestrase; ChGly; SWOT analysis; Polyphenols; X; GlcEg; GlcGly; ee; ChEg; GlcFruScu; PME; SWOT; D-limonene; NADES; η; Biorefinery; SorEg; (R)-1-phenylethanol
• ISSN: 0956-053X; 1879-2456
• DOI: 10.1016/j.wasman.2020.11.052

[Display omitted] •NADESs were screened for valorisation of orange peel waste.•The use of NADESs enhances enantioselectivity of orange peel-catalysed synthesis.•NADESs serve as excellent solvents for extraction of biologically active compounds.•Stabilisation of hydrolytic enzymes (including PME) in NADESs was confirmed.•ChEg50 can serve as a unique solvent for orange peel waste integrated biorefinery. This research investigates the use of seven natural deep eutectic solvents (NADESs) for valorisation of orange peel waste, with the final goal to propose a unique NADES for integrated biorefinery. Initial screening of NADESs revealed the excellent ability of cholinium-based NADES with ethylene glycol as hydrogen bond donor (ChEg50) to serve as a medium for orange peel-catalysed kinetic resolution (hydrolysis) of (R,S)-1-phenylethyl acetate with high enantioselectivity (ee = 83.2%, X  = 35%), as well as it’s stabilizing effect on the hydrolytic enzymes (hydrolytic enzymes within ChEg50 peel extract were stabile during 20 days at 4 °C). The ChEg50 also showed a satisfactory capacity to extract D-limonene (0.5 mg gFW−1), and excellent capacity to extract polyphenols (45.7 mg gFW−1), and proteins (7.7 mg gFW−1) from the peel. Based on the obtained results, the integrated biorefinery of orange peel waste using ChEg50 in a multistep process was performed. Firstly, enantioselective kinetic resolution was performed (step I; ee = 83.2%, X  = 35%), followed by isolation of the product 1-phenylethanol (step II; h = 82.2%) and extraction of polyphenols (step III; h = 86.8%) from impoverished medium. Finally, the residual orange peel was analysed for sugar and lignin content, and results revealed the potential of waste peel for the anaerobic co-digestion process. The main bottlenecks and futures perspective of NADES-assisted integrated biorefinery of orange peel waste were outlined through SWOT analysis.