(161c) Techno-Economic Analysis of a Modular Bioprocess System for Producing Polyhydroxyalkanoates (PHAs) from Food Waste Via Heterogeneous Fermentation.

Plastic pollution is among the most significant challenges the world faces. Annually, 350 million tons of petroleum-based plastic waste are produced, and estimated to reach 500 million tons by 2050. The packaging industry is the largest and growing consumer of synthetic plastics derived from fossil fuels, accounting for 26% of the total volume of plastic used. Plastic pollution detrimentally impacts environmental and human health by contaminating ecosystems, including soil and groundwater, due to its non-biodegradable nature. PHA, a Bioplastics, can be produced from organic waste, such as food waste, via fermentation by using different types of cultures and possesses physicochemical properties resembling or superior to common petroleum-based plastics. However, the variability of food waste properties poses technical challenges for bioplastic production efforts. Heterogeneous fermentation of food waste, utilizing advanced bioprocessing techniques and specialized microbial cultures, can handle diverse food waste compositions. This study evaluates the techno-economic feasibility of a modular bioprocess system that converts food waste into PHAs via heterogenous fermentation using specialized microbial cultures.

A process model of the PHA production targeting specific components of food waste (FW) was developed using BioSTEAM. A simulation was performed to estimate the mass and energy balance of the plant, assuming that 450MT/day of FW is processed in a day. The mass balance showed conversion yields of 104MT of PHA from 450MT food waste (FW) per day, of which 300MT regular food waste,100MT high salinity glycerol waste, and 50MT FOG. The recovered PHA biopolymer will be further used for both flexible and rigid packaging products. We estimated capital costs and the PHA minimum selling price (MSP) from the preliminary economic analysis. The fixed capital investment is estimated at about $77 million, and the minimum Selling Price (MSP) is $3.67/kg, which falls within the market price range of ($2-$7)/kg. The result showed that capital expenses are mainly attributed to equipment, especially the anaerobic digester, and fermenter, totaling $28 million. For Operating Costs, utilities and raw materials constitute the significant expenses. Sensitivity analysis indicates that PHA yield is the most sensitive parameter, followed by the costs associated with fermentation culture and solvent used in the extraction process. Power consumption and electricity prices have a significant impact on the MSP. These results indicate that producing PHA through the heterogeneous fermentation of food waste offers a promising solution for food waste management. Future work will investigate the lifecycle impacts of the technology.