The imminent need for fossil fuel independence in EU countries has led to an increased development of organic waste valorisation technologies for the production of biomethane and chemical building blocks, such as bio-succinic acid (SA). In this work, the potential of two confectionery waste, in the form of wastewater (SCWW) or a side-stream rejection (SSCW), as inexpensive carbon sources for simultaneous SA production and biogas upgrading was evaluated for the first time. Both substrates were tested batchwise with evolved Actinobacillus succinogenes cultures at different nutrient conditions, SSCW at 100 g L-1 resulting in the highest titres/productivities (∼80 g L-1 and 1.3 g L-1h-1, respectively). Then, simultaneous biogas upgrading under continuous gas feeding was studied at bioreactor-scale, higher gas residence times and pressurization leading to desirable biomethane purities (>98%). The research here conducted is crucial for the cost-effectiveness and scale-up of the technology along this new waste-based biorefinery concept.
Keywords: Actinobacillus succinogenes; Biogas upgrading; Biosuccinic acid; Carbon dioxide reduction; Confectionery waste valorisation.
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