Food Waste Biorefineries: A Second Chance for Food Waste

Waste biorefineries? The term “refinery” is commonly associated with the transformation of raw material of fossil origin. However, if we are going to reverse the effects of climate change, wouldn’t it be now the time to have processes and facilities that turn waste into something useful? Energy? Fertilizers? Enzymes? It’s already possible!

7 min. read

The challenges that humanity currently faces are evident. A population that will grow from approximately 7.8 to 9.6 billion inhabitants by the year 2050. Greenhouse gases (GHG) emissions that pollute the environment. Waste management problems that will only multiply with the increase in population, specifically, 2.2 billion tons of garbage in urban centers in 20251. Moreover, it is important to emphasize that these difficulties are more challenging to cope with in developing countries, which deal with obstacles at the “budget, infrastructure and maintenance facilities2” levels. With this scenario in mind, a question remains: What do we do with waste? This is where the biorefinery alternative takes stage with organic, chemical and thermochemical processes for the transformation and creation or reuse of energy, compounds or materials made out of waste.

And what do waste biorefineries consist of? Well, there is no standard, since “the desired form of energy or bioproducts determine the technology route for a biorefinery, followed by the availability and quantities of feedstock3“. However, their objective is similar and it is to bring solutions to the growing challenge of waste management, especially in the cities of the developing world, where only 60 per cent of the garbage is collected and the rest is lying on the streets or in open air dumps4. Furthermore, it is vital not to threaten the food supply, hence the innovation and use of technologies that take advantage of waste and residues such as: thermochemical processes (like pyrolysis, incineration, plasma arc gasification, carbonization and liquefaction) used to produce different types of energy; extraction and transesterification that use chemical agents, which function to obtain liquid fuels and bioproducts, or organic or biochemical processes such as fermentation that use biological agents to transform raw materials into liquid and gas fuels and bioproducts5. The potential is enormous, and it would alleviate economic, environmental and public health demands.

The topic of the types of waste or residues used in biorefineries deserves its own section since it has a direct connection with the circular bioeconomy. Food waste is a global problem, where a third of the food intended for human consumption (spoiled food, abandoned crops in the fields, fruit and vegetable waste, leftover food from homes, restaurants and hotels) ends up in the garbage, and causes economic loss of a trillion dollars, generates pollution and there is even a nutritional loss6. To eliminate completely food waste is utopian, but reducing it is feasible. This is where food waste biorefineries come into action, by reusing food waste with the previously mentioned processes, they generate energy (biofuels) and produce chemicals or materials (platform chemicals, bioproteins and enzymes, biopolymers, biofertilizers, phenolic compounds, pectin and essential oils)7. Clearly, the principles of bioeconomy are applied. In the case of Ecuador, “the beer, vegetable oil, banana, cacao, coffee, rice, rose export industries… are potential sources of bioenergy, biomaterials and bioproducts8“.

The prospect of circular bioeconomy in food industries
Adapted from Tsegaye B. et al., 2021

The future of biorefineries is promising, however, there are considerations that must be taken into account. It is necessary to overcome difficulties in accessing adequate biomass because not all of it is suitable for transformation or reuse. Municipal solid waste (MSW) is found in the largest quantity, but it can be very heterogeneous and may require several processes to obtain useful products. In addition, not all the uses that could be given to waste are the most sustainable, since some existing use can be replaced, and therefore, have a negative impact on the environment. However, the creation of biomass availability databases; understanding that food waste biorefineries can coexist with other types of facilities as an integrated system, and promoting the advancement of technologies that will allow the processing of never-before processed compounds or more sustainable processes will definitely add value to products or materials manufactured in biorefineries, and that will address the above concerns9.

The benefits that the implementation and optimization of food waste biorefineries would bring are undeniable: independence from fossil fuels and reduction of the carbon footprint, energy recovery with the production of biofuels, reuse of resources, protection of human health and the environment, in addition to promoting research and development to advance the technology used in biorefineries10. However, there are still restrictions on what can be achieved with this technology. There are types of biomass that cannot be transformed with existing processes. The adequate biomass for its reuse is not found in the necessary quantities. It is time to promote these technologies, since the environmental and economic challenges that our planet faces are increasingly overwhelming. We need solutions that come from the circular bioeconomy, so that they are sustainable and reduce our trail of waste.

1 Nizami A.S.,  Rehan M., Waqas M., et al. 2017. Waste biorefineries: Enabling circular economies in developing countries. Bioresource Technology. p.1104
2 Ibid. Nizami A.S.,  Rehan M., Waqas M., et al. 2017. p.1102
3 Ibid. Nizami A.S.,  Rehan M., Waqas M., et al. 2017. p.1108  
4 Ibid. Nizami A.S.,  Rehan M., Waqas M., et al. 2017. p.1102
5 Tsegaye B., Jaiswal S, and Jaiswal A. K. 2021.Food Waste Biorefinery: Pathway towards Circular Bioeconomy. Foods. p.1
6 Id.
7 Ibid. Tsegaye B., Jaiswal S, and Jaiswal A. K. 2021. p.8
8 Orejuela Escobar L.M. 2018. Biorefinería: un modelo de negocios de productos de alto valor agregado a partir de desechos agrícolas e industriales y promotora de desarrollo sustentable en el contexto de la bioeconomía. Casa Editora Universidad del Azuay. p.199
9 Sadhukhan J., Martinez-Hernandez E., Siew Ng K. 2016. Biorefinery value chain creation. Chemical Engineering Research and Design. p.1-3
10 Ibid. Sadhukhan J., Martinez-Hernandez E., Siew Ng K. 2016. p. 1