Executive Summary : | Petroleum-derived plastics pose environmental issues such as plastic waste in water bodies and microplastics. Biodegradable plastics like polylactic acid (PLA) can address these issues by replacing them with lactic acid (LA), which can be synthesized through fermentation of sugars and cornstarch. However, the production of LA requires a large volume, which raises ethical concerns, is not feasible for commodity chemicals, and the separation process is complex and expensive. To address these issues, a proposal is proposed to lower the cost of production by using sugars from agricultural or food waste (AFW) as a renewable organic carbon source. The fermentation process can be intensified using continuous fermentation in a packed bed reactor or a membrane bioreactor, reducing fermentation costs and minimizing processing steps. LA secreted in fermentation media can be purified using switchable adsorbents or capacitive deionization (CDI). LA is negatively charged in solution, so adsorbents that acquire a positive charge can be used to elute the adsorbate at high efficiency. CDI electrodes are similar to adsorbents but with an electric field driving force, resulting in increased cycle times and electrode capacity. The adsorption in CDI can be tuned precisely through material properties, flow, and electrical potential, resulting in excellent separation in short time. The overall life cycle assessment of LA production and comparison to conventional methods is also a key aspect of the proposal. |