From waste to value: Utilisation of lignin streams as raw materials for the production of chemicals and biofuels
Lead Research Organisation:
Imperial College London
Department Name: Chemical Engineering
Abstract
A transition from fossil-based to a sustainable economy is one of the major challenges humanity faces in the foreseeable future. Lignocellulosic biomass is one of the most abundantly available materials on Earth and can potentially serve as an alternative for crude oil for chemicals and fuels production. While currently only a fraction of lignocellulosic material is utilised in pulp production, it is desired to valorise the biomass fully, offering alternatives to fossil-derived products.
Lignin, a polymeric component of lignocellulosic biomass constitutes around one-third of the mass of wood. It is the only abundant source of aromatics in nature. During the PhD programme, I aim to work at the forefront of lignin valorisation by developing new novel methods for wood fractionation as well as work on development of the end-products. This allows me to develop a deep understanding of lignocellulosic biomass properties and lignin chemistry.
During the PhD programme, I will focus on developing methods for catalytic upstream biorefining (CUB) and discover the possible end-products which can be synthesised from platform chemicals obtained with CUB. To enhance and understand the catalytic fractionation of lignin in wood, ternary mixtures of fluorinated alcohols will be exploited along with isopropanol and water.
Lignin, a polymeric component of lignocellulosic biomass constitutes around one-third of the mass of wood. It is the only abundant source of aromatics in nature. During the PhD programme, I aim to work at the forefront of lignin valorisation by developing new novel methods for wood fractionation as well as work on development of the end-products. This allows me to develop a deep understanding of lignocellulosic biomass properties and lignin chemistry.
During the PhD programme, I will focus on developing methods for catalytic upstream biorefining (CUB) and discover the possible end-products which can be synthesised from platform chemicals obtained with CUB. To enhance and understand the catalytic fractionation of lignin in wood, ternary mixtures of fluorinated alcohols will be exploited along with isopropanol and water.
Organisations
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| EP/R513052/1 | 01/10/2018 | 30/09/2023 | |||
| 2292577 | Studentship | EP/R513052/1 | 01/10/2019 | 31/03/2023 | Raul Rinken |
| Description | Lignin-first biorefining (LFB) is an emerging biorefining strategy where lignin valorisation is considered already in the design phase. One of the most widespread and promising LFB approaches is Reductive Catalytic Fractionation (RCF) (previously known as Catalytic Upstream Biorefining), which produces monomeric aromatic molecules, polymeric lignin, hemicellulose-derived molecules, and high-quality polysaccharide pulp. Depending on the RCF reaction conditions, a significant proportion of the lignin remains polymeric. However, the properties and nature of the polymeric lignin from RCF have received very little attention to this date. To tackle the challenge, a solvent fractionation strategy was developed to isolate different RCF lignin fractions and profile them. As a result, a new feature in polymeric RCF lignin was discovered, shedding light on a new reaction mechanism stabilising the lignin during the RCF process. It was demonstrated that, unlike the lignins from current industrial processes, the high molecular weight RCF lignin is rich in native lignin linkages, and the catalytic process could allow obtaining mid- and high molecular weight lignin with controllable properties. Furthermore, this would enable high-value applications for polymeric lignin and open pathways to new classes of polymers. As a part of lignin oil characterisation, it was discovered that the hemicellulose-derived carbohydrates present in the lignin oil have different structural features than were known before. Namely, one end of the oligomeric carbohydrates is reduced during the RCF process, giving rise to oligosaccharide alcohols. This finding helps to assess better the amount of carbohydrates in lignin oils as well as to develop strategies to tackle the hemicelluloses valorisation from lignocellulosic biomass. Apart from structural characterisation, strategies to enhance the outcomes of the RCF were developed. The manuscripts for the two approaches are currently in preparation. One method relies on mechanical pretreatment along with commodity reagents, which allows controlling the cellulose and hemicellulose retention along with the aromatic monomers' yield and distribution. The other strategy involves a semi-batch approach, where different types of molecules are extracted at different phases of the RCF process. |
| Exploitation Route | The high molecular weight lignin fractions isolated from RCF lignin oil could be further investigated and can hold significant potential for valorisation as the native structure of lignin is retained. Studies for new materials using lignin as a precursor could open up new high-value applications. Furthermore, the discovered feature introduced to polymeric lignin in the RCF process could be a key to creating highly stable polymeric lignin with controllable structural features. Further research would be necessary to broaden the understanding of the feature and develop methods to enhance it. Further investigation of mechanical pretreatments in the presence of reagents could help to further improve the outcomes of RCF by increasing the yield and creating a more uniform distribution of the monoaromatic compounds. This and methods developed in the other labs could play an essential role in RCF commercialisation and potential large-scale production. |
| Sectors | Agriculture, Food and Drink,Chemicals,Energy,Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology |