Lignin recovery from cocoa bean shell using microwave-assisted extraction and deep eutectic solvents

Yujie Mao; Alex Gerrow; Ella Ray; Nidia Diaz Perez; Karen Edler; Bettina Wolf; Eleanor Binner

doi:10.1016/j.biortech.2023.128680

Lignin recovery from cocoa bean shell using microwave-assisted extraction and deep eutectic solvents

Bioresour Technol. 2023 Mar:372:128680. doi: 10.1016/j.biortech.2023.128680. Epub 2023 Jan 24.

Authors

Yujie Mao¹, Alex Gerrow², Ella Ray³, Nidia Diaz Perez⁴, Karen Edler⁵, Bettina Wolf⁶, Eleanor Binner⁷

Affiliations

¹ Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Nottingham, University Park, Nottingham NG7 2RD, UK. Electronic address: Yujie.Mao1@nottingham.ac.uk.
² School of Chemical Engineering, University of Birmingham, Edgbaston Campus, Birmingham B15 2TT, UK. Electronic address: AXG1002@student.bham.ac.uk.
³ Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Nottingham, University Park, Nottingham NG7 2RD, UK. Electronic address: enyejra@exmail.nottingham.ac.uk.
⁴ Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Nottingham, University Park, Nottingham NG7 2RD, UK. Electronic address: Nidia.Diazperez1@nottingham.ac.uk.
⁵ Centre for Analysis and Synthesis, Department of Chemistry, University of Lund, Naturvetarvägen 14/Sölvegatan 39 A, 223 62, Sweden. Electronic address: karen.edler@chem.lu.se.
⁶ School of Chemical Engineering, University of Birmingham, Edgbaston Campus, Birmingham B15 2TT, UK. Electronic address: b.wolf@bham.ac.uk.
⁷ Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Nottingham, University Park, Nottingham NG7 2RD, UK. Electronic address: Eleanor.Binner@nottingham.ac.uk.

PMID: 36706816
DOI: 10.1016/j.biortech.2023.128680

Abstract

Lignin is the second most abundant natural polymer after cellulose, and valorisation of lignin-rich streams has attracted increasing attention recently. This paper presents a novel and sustainable method to recover lignin from Cocoa Bean Shells (CBS) using Deep Eutectic Solvents (DES) and microwaves. A DES containing p-toluenesulfonic acid, choline chloride and glycerol (2:1:1 M ratio) was selected based on its dielectric properties. Under 200 W microwave power, the optimum yield of 95.5 % lignin was achieved at 130 °C and 30 min. DES-extracted lignin exhibited unique structural characteristics including larger particle sizes (242.5 µm D50 size), structural diversity (410.4 µm D90-D10 size) and H/G sub-unit ratio (71.9 %) compared with commercial Kraft lignin (77.2 µm, 157.9 µm and 0.1 % respectively), indicating the potential of DES in the modification and upgrading of lignin for novel value-added products.

Keywords: Deep eutectic solvents; Dielectric properties; Lignin; Microwave-assisted extraction; Waste valorisation.

MeSH terms

Biomass
Cellulose
Deep Eutectic Solvents
Lignin* / chemistry
Microwaves*
Solvents / chemistry

Substances

Lignin
Deep Eutectic Solvents
Solvents
Cellulose