[16-FAPESP-BE] Lignin valorization in cellulosic ethanol plants: biocatalytic conversion via ferulic acid to high value chemicals

Lignin is a polymer found in plant cell walls, and is the most abundant source of renewable aromatic material on Earth. Lignin therefore represents a valuable raw material for generation of renewable chemicals, which will help society to reduce its dependance on crude oil for production of chemicals and materials such as plastics.
Converting lignin into renewable chemicals is a very difficult challenge, because it is very hard to break down, and it is very heterogeneous (mixture of different structural units). Researchers at Warwick University have recently discovered several soil bacteria that can break down lignin, and specific enzyme biocatalysts that can oxidise lignin, and through a BBSRC/FAPESP FAPPA award have collaborated with CTBE in Brazil to identify new lignin-degrading enzymes through genome sequencing, and to develop new "biosensors" that could be used to engineer recombinant lignin-degrading micro-organisms that could break down lignin to high-value chemicals.

The proposal brings together expertise in cellulosic ethanol production and metagenomic DNA sequencing (CTBE) with expertise in biocatalytic lignin valorisation (Warwick) and biocatalysis for high value chemicals production (Manchester, UCL). The overall aim is to use synthetic biology to break down lignin to intermediate ferulic acid, which has been generated from lignin via bacterial fermentation in previous work, and then to convert ferulic acid via biocatalysis into high-value chemicals. The project will : 1) optimise a lignin stream for the project from cellulosic bioethanol production at the CTBE pilot plant; 2) convert lignin into ferulic acid from lignin using synthetic biology; 3) enzymatically convert ferulic acid into a high-value pharmaceutical chemical, L-Dopa; 4) generate high value fragrance chemicals (coniferyl acetate, isoeugenol) from ferulic acid; 5) scale up chemicals production from renewable feedstocks; 6) assess the technical and sustainability impact of the methods developed in the project.

Lignin can be obtained as a by-product of cellulosic ethanol production, and is a potential source of renewable chemicals. Efficient valorisation of lignin is a major unsolved problem in the development of sustainable biorefineries. The proposal builds upon an existing BBSRC/FAPESP FAPPA partnership award, and brings together expertise in cellulosic ethanol production and metagenomic DNA sequencing (CTBE) with expertise in biocatalytic lignin valorisation (Warwick) and biocatalysis for high value chemicals production (Manchester, UCL). The overall aim is to generate new methods for lignin valorisation via intermediate ferulic acid, which has been generated from lignin via bacterial fermentation in previous work. The project will involve the following work packages: 1) optimisation of lignin generation from cellulosic bioethanol production; 2) conversion of lignin to ferulic acid from lignin using synthetic biology; 3) enzymatic conversion of ferulic acid into pharmaceutical L-Dopa; 4) biocatalytic generation of high value fragrance chemicals (coniferyl acetate, isoeugenol) from ferulic acid; 5) bioprocess intensification and scale-up of chemicals production from renewable feedstocks; 6) technical and sustainability impact assessment. Technology developed in the project could be applied to major plant feedstocks used in Brazil (sugarcane) or the UK (wheat).

This work will be of interest to academic & industrial scientists working in the areas of bioenergy & biorefinery research, and scientists working in enzymology. There is considerable academic interest in the conversion of lignocellulose into biofuels and renewable chemicals, as evidenced by the BBSRC BSBEC Centre and the BBSRC IBTI Biorefinery Club, of which TDHB has been a member. TDHB is the co-PI of a new BBSRC-funded Network in Industrial Biotechnology and Bioenergy, the Lignocellulosic Biorefinery Network (LBNet). This Network will provide an ideal mechanism to disseminate the results of the project to Academic and Industrial groups working in the area of Industrial Biotechnology and Bioenergy. There is also considerable interest around Europe in the Bio-Based Economy, and a great deal of interest in America in biomass conversion to biofuels and renewable chemicals. Hence, the identification of new lignin-degrading genes and enzymes will be of considerable interest to academics working in biotechnology and enzymology around the world. The results arising from the project will be published in international scientific journals, after consideration of possible intellectual property in the work.

The project will also provide a valuable training in protein biochemistry for biotechnology for the PDRAs employed on the project, as there is a growing biotech industry in the UK for biofuel/renewable chemicals production who will need highly skilled personnel.

The project has the support of Brazilian industrial partner Natura, who are interested in the production of fragrance chemicals from renewable sources. Although the project is for basic/early stage research, it is quite possible that outcomes of the project will lead to patentable results and processes. There will be a collaboration agreement drawn up within 3 months of the start of the project to manage intellectual property arising from the project.

The discovery of biocatalytic routes from lignin and lignocellulose to high-value chemicals will be of considerable interest to the biofuel industry, which is already highly developed in Brazil. CTBE has close links with Brazilian biofuel companies, with whom i twill disseminate the outputs of the project. Within the UK, TDHB collaborates with Biome Bioplastics to produce feedstock chemicals for bioplastics production, and NJT collaborates with a range of fine chemicals and fragrance companies to whom the outputs of the project will be disseminated in the UK.

The work will also be of interest to the wider public. There is considerable public interest in "green" issues, and the use of biotechnology to convert biomass into renewable chemicals (i.e. useful products from agricultural or even domestic green waste) will be of considerable interest. For our previous BBSRC-funded project we prepared a podcast "Renewable Chemicals from Lignin" in August 2012 which is available from TDHB's research group web-site. The results of the project will also be disseminated to the general public and local community through a range of events. The Department of Chemistry has an active Outreach programme, managed by Teacher Fellow Nick Barker (a former secondary school chemistry teacher), who organises with a wide range of events (laboratory workshops, lectures in schools, events for teachers) with a cross-section of Warwickshire schools, contacting >2,000 school pupils each year.