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Agroindustrial waste as a resource for carboxylic acids production

Volatile fatty acids (VFAs) are carboxylic acids, ranging from acetic acid to caproic acid, considered valuable building blocks for the chemical industry since they are precursors of reduced chemicals (alcohols, aldehydes or ketones). However, these acids are traditionally produced through petrochemical routes. The search for renewable sources together with environmental concerns related to the use of fossil fuel is boosting the need of developing new production models. In this context, the production of VFAs through biological processes such as anaerobic fermentation of organic wastes is an interesting option. During the anaerobic fermentation process, the carbohydrates, proteins and lipids present in organic wastes are transformed into VFAs by a synergic microbial community in absence of oxygen. 

In the last years, a wide range of organic compounds has been used as feedstock for anaerobic fermentation including sewage sludge coming from wastewater treatment plants or the organic fraction of municipal solid wastes. In this perspective, agroindustrial wastes are considered promising feedstocks for VFAs production via anaerobic fermentation due to its high biodegradability and its large availability. Nowadays, agriculture is one of the industrial sectors that generates the largest amount of residues. 1.3 billion tonnes of food are wasted each year during its production, handling, storage, processing, distribution or consumption. The most common managing methods (landfilling, composting or incineration) involve high management costs and a negative environmental impact. Therefore, the use of agroindustrial wastes as feedstocks for VFAs production supports a more sustainable and cost-effective approach to handle agricultural wastes. This approach promotes a win-win situation where wastes are not only reduced and treated but also valorised as bioproducts and hence, contributing to circular economy.

The Biotechnological Processes Unit at IMDEA Energy has recently published a scientific article* where the anaerobic fermentation of agroindustrial wastes to produce VFAs was assessed taking into account the effect of the operational parameters on the microbial community involved in the optimization of VFAs production. Remarkably, high process efficiency resulted from this research study demonstrating that anaerobic fermentation of carbohydrate-rich wastes is a feasible bioprocess to valorise agroindustrial wastes as VFAs.

(*) Greses, S., Tomás-Pejó, E., González-Fernández, C. AGROINDUSTRIAL WASTE AS A RESOURCE FOR VOLATILE FATTY ACIDS PRODUCTION VIA ANAEROBIC FERMENTATION (2020) Bioresource Technology 297, 122486. https://doi.org/10.1016/j.biortech.2019.122486 

More information: Silvia Greses, Postdoctoral researcher, Biotechnological Processes Unit silvia.greses@imdea.org

Figure 1. VFAs obtained during the steady state of the reactor fed with cucumber (CSTR-C), tomato (CSTR-T) and lettuce (CSTR-L) and their corresponding bioconversion efficiencies. 

Figure 2. Microbial community present in the inoculum as well as in the anaerobic fermenters fed with cucumber (CSTR-C), tomato (CSTR-T) and lettuce (CSTR-L) at (a) phylum and (b) genus levels. 

Figure 3. Anaerobic fermenters used to bioconvert agroindustrial wastes into VFAs.



Event Date: 
Monday, July 6, 2020