b'Up-cycling ProcessBiochemical digestion of gamma irradiated polyethylene by the fungus Feasibility for CoupledNeurospora crassa in anaerobic saltwater conditions is not practical. Radiolytic and BiochemicalT here are currently no sustainable industrial scale processing routes for the recovery and conversion of low value plastics such as polyethylene. Conversion of Polyethylene Therefore, they accumulate in landfill waste and contaminate the environment. Due to the absence of sustainable recycling methods, the demand for virgin plastic synthetic feedstocks from petrochemical sources continues to increase and is expected to become a significant energy drain by 2050. From both an energy and environmental standpoint, this unsustainability has prompted DOE to encourage the development of sustainable plastic recycling methods because the billions of PROJECT NUMBER:tons of waste plastic are potential sources of cost-effective synthetic feedstocks. 21A1055-015 However, unlike several other types of plastic, such as polyesters, polyethylene does not contain any chemical functionality beyond its carbon-hydrogen backbone, TOTAL APPROVED AMOUNT:essentially making it chemically and biologically inert unless extreme conditions or $125,000 over 1 year exotic processes are employed. The research presented here investigated the proof-PRINCIPAL INVESTIGATOR:of-concept of using gamma irradiation capabilities at INL to initiate the chemical Gregory Horne functionalization and depolymerization of polyethylene micro- and nanoplastics blended into aqueous solutions (water and saltwater), followed by biochemical CO-INVESTIGATORS: conversion at Valparaiso University to yield useful synthetic feedstocks. This research Corey Pilgrim, INL found that anaerobic conditions and saltwater were not practical for a radiation-Julie Peller, Valparaiso University driven polyethylene up-cycling process. However, the anerobic data gathered by Michael Watters, Valparaiso University this work does provide a baseline for future investigations into the practicality and Stephen Mezyk, California State Universityimpact of aerobic conditions. Biochemical conversion studies using the fungus Long Beach Neurospora crassa found that non-irradiated and anaerobic irradiated polyethylene was unavailable as a carbon source and mostly toxic to the microbes. However, the presence of more functionalized polymers, such as polyethylene terephthalate, afforded viable Neurospora crassa cultures. These latter findings present a promising pathway should aerobic irradiations lead to carbonyl functionality in polyethylene. This work also developed an effective treatment for commercially procured polyethylene to remove residual contaminants, the publication of two peer reviewed manuscripts, dissemination of results through eight presentations, mentoring of 11 students, and the successful award of follow-on funding through the National Science Foundation.72'