Organosolv pretreatment of cocoa pod husks : isolation, analysis and use of lignin from an abundant waste product
Abstract
Cocoa pod husks (CPHs) represent an underutilized component of the chocolate manufacturing process. While industry’s current focus is understandably on the cocoa beans, the husks make up around 75 wt % of the fruit. Previous studies have been dominated by the carbohydrate polymers present in CPHs, but this work highlights the presence of the biopolymer lignin in this biomass. An optimized organosolv lignin isolation protocol was developed, delivering significant practical improvements. This new protocol may also prove to be useful for agricultural waste-derived biomasses in general. NMR analysis of the high quality lignin led to an improved structural understanding, with evidence provided to support deacetylation of the lignin occurring during the optimized pretreatment. Chemical transformation, using a tosylation, azidation, copper-catalyzed click protocol, delivered a modified lignin oligomer with an organophosphorus motif attached. Thermogravimetric analysis was used to demonstrate the oligomer’s potential as a flame-retardant. Preliminary analysis of the other product streams isolated from the CPHs was also carried out.
Citation
Davidson , D J , Lu , F , Faas , L , Dawson , D M , Warren , G P , Panovic , I , Montgomery , J , Ma , X , Bosilkov , B G , Slawin , A M Z , Lebl , T , Chatzifragkou , A , Robinson , S , Ashbrook , S E , Shaw , L J , Lambert , S , Van Damme , I , Gomez , L D , Charalampopoulos , D & Westwood , N J 2023 , ' Organosolv pretreatment of cocoa pod husks : isolation, analysis and use of lignin from an abundant waste product ' , ACS Sustainable Chemistry & Engineering . https://doi.org/10.1021/acssuschemeng.2c03670
Publication
ACS Sustainable Chemistry & Engineering
Status
Peer reviewed
ISSN
2168-0485Type
Journal article
Description
The authors acknowledge the UK Biotechnology and Biological Sciences Research Council (BBSRC) for the financial support through the Global Challenges Research Fund (GCRF) Project “Development of novel value chain from cocoa pod husks in Indonesia: Technological, environmental and socio-economic challenges of a value chain” (BB/P022995/1). EaSI-CAT (Ph.D. studentship to D.J.D.). EPSRC-funded CRITICAT Centre for Doctoral Training (Ph.D. studentship to I.P.; EP/L016419/1).Collections
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