Mining and minding food waste through carboxylate value-added platform

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Globally, food wastes constitute about 30-50% of the municipal solid waste while landfilling remains the main waste treatment technology. In Ontario, a staggering amount of 3.7 M tonnes/year of food and organic waste is generated and about 60% of food waste ends up in landfills. From the circular economy perspective, landfilling of food waste is not a sustainable option in view of greenhouse gases emission and breakdown of nutrient cycling. These factors along with Canada's commitment to Sustainable Development Goal 12.3 to reduce food waste by 50% by 2030 and promote environmental protection, food security, and material and energy efficiency are the key drivers for valorization of food waste. The goal of this program is to create innovative and advanced food waste valorization processes beyond the conventional anaerobic digestion process to build a low carbon and economically efficient circular biobased economy in Canada. This will be achieved through the bioconversion of food waste to carboxylates which are high-value building blocks for the synthesis of a myriad currently fossil-fuel derived products such as polymers (plastics), alcohols (e.g. butanol as biofuel), ketones and olefins. This research program will promote the development of an effective high-value resource recovery system from food waste based on acidogenic mixed culture fermentation incorporating process design and optimization, microbial community engineering, process intensification via coupled upstream-downstream system, and multi-product value-chain including short- and medium-chain fatty acids (SCFA, MCFA), bioplastics and liquid biofuel precursors. Specifically, the program has four primary objectives: (i)Develop innovative bioreactor configurations and operating strategies for enhanced carboxylate production with focus on fed-batch and continuous design systems, high loading conditions and impact of acidogenic gas pressure and composition. (ii)Investigation of microbial community structure and function dynamics to (a) identify specific microbial groups enriched under specific process conditions and produce enhanced and/or desired carboxylates and (b) develop efficient bioaugmentation systems for specific carboxylate synthesis. (iii)Develop coupled fermentation-extraction i.e. in-situ product recovery (ISPR) systems to extract carboxylate from acidogenic fermenter and back extraction protocols for simultaneous alleviation of carboxylate inhibition and their high recovery. (iv) Establish the methods for deriving secondary higher-value products such as MCFA and bioplastics from carboxylates through biotransformation techniques. The program will provide highly qualified personnel (HQP) with modern skill sets and competencies in emerging areas of waste treatment, biorefinery, microbial ecology for engineered systems, and applications of recovered bioproducts. Such skilled HQPs would foster the development of these clean technologies across Canada and around the world.