Newton Fund: From orange waste to chemicals: contributions of an integrated biorefinery approach towards sustainable development in Brazil

There is a pressing need for the use of renewable resources within cascading circular economies to create sustainable production and processing systems. Within this context, biorefineries are vital, as facilities for the conversion of biomass into multiple value-added products, creating flexible, zero waste networks using a variety of 'low' value local feedstocks and contributing significantly to a bio-economy. The main objective of this collaborative project is to strengthen the research network between the Green Chemistry Centre of Excellence (GCCE, the University of York, UK) and the Natural Products Research Group (NPRG, Federal University of São Carlos, Brazil) around valorization of the Brazilian citrus chain waste, based on biorefinery and green chemistry concepts. A techno-economic and environmental assessment of a proposed whole Brazilian citrus chain biorefinery will be performed using methods developed by the SEI green-economy group, including Life Cycle Assessment, encompassing food, energy, water, environmental and social impacts. Initial studies within both groups indicate that there is a wide spectrum of valuable compounds within orange waste that can be economically recovered and modified using green extraction and formulation techniques at both a lab- and larger-scale (including flavonoids, pectin, cellulose, d-Limonene, terpineol, waxes, alkanes, sugars, among others that can be used as additives for personal care products, flavour and fragrances, cosmetics, nutraceuticals, bio-solvents, biopolymers and active ingredients for insect repellents). However, an integrated biorefinary approach to citrus chain waste needs to be further explored and advanced, particularly considering specific Brazilian economic, social and environmental characteristics and to further develop potential uses of higher value compounds. Within this project, events (workshops, conferences, courses, lectures and scientific meetings) and short-research stays will aim to transfer knowledge and technological expertise and will be of utmost importance in building long-term partnerships between the GCCE and NPRG groups, who are considered references within their areas of expertise across the world (e.g., green technologies and waste valorization at GCCE, sustainable agriculture and natural insect control at NPRG). The creation of links between these groups will aim to generate immediate results as well as future research proposals on orange waste exploitation, contributing to sustainable development in Brazil. This innovative initiative will also support the development of a new Centre of Excellence in Green Chemistry and Sustainability based in São Carlos (SP), as a full member of the Global Network of Green Chemistry Centres (G2C2). The Centre will promote and deepen dialogue between the academia, government and industry sectors, helping to constitute a better equipped community to develop excellent research outcomes and related activities around sustainability and green chemistry within Brazil.

The biorefinery integrates facilities for the conversion of biomass into multiple value-added products, to create flexible, zero waste networks, using a variety of 'low' value local feedstocks, contributing significantly to a bioeconomy. To ensure the sustainability of this approach it also necessary to evaluate the full social, environment and economic impacts including energy usage, biomass supply, impacts on water quality and market competitiveness.

In Brazil, it is estimated that 898 to 1,402 million tonnes/year of agricultural, agro-industrial and forestry waste will be produced from 2015 to 2030. Soybean, corn, sugarcane and citrus are among the main types of biomass generated in the country, with around 7.7 million tonnes of waste orange peel generated from fruit processing during the 2010/2011 harvesting season. São Carlos (SP) is located in a land-belt with more than 80% of Brazil's citrus production, and the NPRG has established connections with several citrus companies and research institutions, including Fundecitrus. Since 2011, the GCCE has been developing the OPEC project (Orange Peel Exploitation Company), valorising orange waste using sustainable chemistry. The potential operating profit generated by commercialising these co-products has been estimated at £7.3 million per 10,000 t/pa wet waste (based on £11.8 million for pectin and £94,032 for d-limonene). The OPEC results show that there is a wide spectrum of compounds with many applications within citrus wastes (e.g., flavonoids, pectin, cellulose, d-Limonene, terpineol, waxes, alkanes, sugars), and many green methods and techniques that can be employed in lab- and large-scale processes. Potential envisaged applications for these co-products are in personal care products, cosmetics, nutraceuticals, flavours, fragrances, bio-solvents, biopolymers and active ingredients for insect repellents. The NPRG has extensive experience in the development of natural product formulations including for the biorational control of pests [e.g., Atta sexdens rubropilosa (ants) and Diaphorina citri of citrus], using plants, their extracts, isolates or complexes of such compounds (e.g. pyridinic complexes of Ru and Mg such as [Ru(phen)(L)+L, where L was hesperidin, hesperetin, naringin or naringenin). In addition, the NPRG has state-of-the-art facilities for analysis of high-value extracts such as semi-solid NMR, HPLC-SPE-FT-NMR, electrophoresis, HS-GCxGC-MS/MS and counter-current chromatography. The broad knowledge and technical expertise across both groups will be utilised including in high-throughput screening, nanotechnology and green extraction techniques. A partnership between the GCCE and NPRG will therefore enable an exchange of knowledge and technology around citrus waste valorisation focusing on the citrus industry within São Paulo State.

This work will build on research from two of the GCCE's EPSRC projects. The Materials Substitution project uses limonene as a key feedstock. This proposal will enable further sustainability improvements through testing the applicability of novel technologies at scale and LCA analysis. Furthermore, the proposal will utilise experience on microwave hydrolysis and high-throughput techniques to produce new higher value chemicals from citrus waste.

It is also proposed to build a network of collaboration among researchers from various federal and state universities and research institutes in order to foster the research involving the application of the integrated citrus waste biorefinery approach in Brazil. This innovative initiative will permit the creation of a new Centre of Excellence in Green Chemistry and Sustainability based in São Carlos, Brazil, as a full member of the global network "G2C2", in order to promote and deepen the dialogue between the government, academia and industry sectors.