High-Temperature, Noncatalytic Oxidation of Polyethylene to a Fermentation Substrate Robustly Utilized by <i>Candida maltosa</i>
Jessica L. Brown, Efrain Rodriguez-Ocasio, Chad A. Peterson, Mark Blenner, Ryan Smith, Laura R. Jarboe, Robert C. Brown
Abstract
This study applies thermal oxo-degradation (TOD) of plastics to produce substrates suitable for uptake and utilization by some microbial species. At moderate temperatures (500 °C) in a noncatalytic, oxidative environment, TOD rapidly deconstructs high-density polyethylene (HDPE) producing a mixture of hydrocarbons, alcohols, aldehydes, and carboxylic acids. Three yeast species were examined for their ability to utilize TOD as the sole carbon source. Candida maltosa showed growth similar to that observed on glucose. Growth of Scheffersomyces stipitis was observed but at a greatly reduced level relative to glucose. Growth of Saccharomyces cerevisiae was negligible. For C. maltosa and S. stipitis, the added oxygen functionality of TOD products dramatically expedites and improves microbial utilization of the degraded plastic product over that of the pyrolysis product, offering a novel process for funneling waste plastics into microbial metabolic pathways.