Biorefining hemicelluloses and lignin from sugarcane bagasse

Abstract

In recent years, and in spite of financial hurdles, Brazil and the UK have committed to decarbonise their economies and embrace a NetZero economy. The UK government published its Net Zero strategy in 2021, where the roadmap for the technological transition to decarbonise the UK economy is laid out. In a similar way, Brazil has committed to reach net zero carbon emissions by 2050, with a market-led approach. Both countries recognise the role of biomass utilisation in decarbonising the economy by displacing oil based fuels, chemicals and materials. The UK government has set out the role biomass can play in reaching net zero in its Biomass Strategy document (2023). Brazil, on the other hand, has centred the use of biomass to decarbonise its economy on the existing industrial ecosystem built around the valorisation of sugarcane. Brazil produces around 30% of the world's ethanol, allowing the displacement of fossil fuels in their energy matrix to the point that the majority of the energy mix is based on renewables. The scale of ethanol production means that bagasse, the biomass fraction remaining after sugarcane is processed, accumulates at a rate of 160,000 tons/year. Bagasse represents the most realistic route to second-generation (cellulosic) ethanol that would further reduce the emissions in the transport sector. Brazil has carried out long term research to reduce the cost of processing bagasse into ethanol. These efforts in developing this process have led to the only second-generation ethanol producing plant in the world. Indeed, our industrial partner Raizen (see letter of support) is the leader in the biorefining sector in Brazil and at present they are commissioning their first commercial plant. Four additional plants are under construction, from a total of 8 plants from which the 2G ethanol is already sold. Raizen have made a public commitment of building 20 E2G plants by 2030. Brazil's leadership in biorefining has driven other countries in the region to develop an active sector in sustainable energy. One of the consequences of the large-scale operation of biorefineries is the production of waste streams that match in scale the large amount of final products reaching the markets. Although at present these waste streams are burnt for energy, the operation of these biorefineries has highlighted the need for further valorisation of waste streams requiring a cascade of processes that consolidate the financial sustainability of the whole biorefinery. Developing new bioproducts from biomass streams (C5 sugars and lignin), would add value to sugarcane biorefinery industry and meet the growing demand for green chemicals. These fractions are frequently burnt to generate heat and power; however, they have an intrinsic potential for the production of high value chemicals. The proposed collaboration between CNAP, and the University of Sao Paulo (USP) aims to explore biochemical conversion routes of hemicelluloses and lignin to produce valuable chemicals. The project will bring together several research groups at CNAP (Federico Sabbadin, Leonardo Gomez and Neil Bruce), the Biorenewables Development Centre (Deborah Rathbone) at York, as well as groups from USP (Igor Polikarpov, Fernando Segato & Carlos Labate) and industrial contribution from Raizen (Lima, Arnoldi). The research work described in the application will be largely carried out by research students at USP with support from the postdoc Katrin Besser and research technician on our BBSRC funded project "Unlocking the metabolic potential of the exceptional lignocellulose degrading fungus Parascedosporium putredinis N01" (BB/W000695/1). The results from this project and the workshops to be held in Sao Paulo and York will aim to produce a UKRI/FAPESP application in the first year of the collaboration. (AU)