2025 AIChE Annual Meeting

(688b) The Evolution and Use of Candida Maltosa As a Microbial Cell Factory for Bioconversion of Plastic Thermal Oxo-Degradation Product

Authors

Laura R. Jarboe, Iowa State University
Mark Blenner, University of Delaware
The thermal oxo-degradation (TOD) of plastics can produce a waxy, solid substrate that can be used as carbon and energy source of microbial cell factories. We have observed that HDPE-derived TOD is a complex mixture of hydrocarbons, alcohols, carboxylic acids and aldehydes. A survey of 14 yeast species for utilization of 18 model compounds identified Candida maltosa as a promising microbial cell factory for TOD utilization. This finding was validated by the experimental observation that C. maltosa outperformed Scheffersomyces stipitis and Saccharomyces cerevisiae for utilization of HDPE-derived TOD. C. maltosa was subjected to adaptive laboratory evolution for faster growth on HDPE TOD increased the specific growth rate by more than 200%. Additional characterization revealed that C. maltosa secretes biosurfactants to solubilize TOD components, and the organism evolution impacted the biosurfactant production such that the solubility of fatty alcohols and alkanes and emulsification of alkanes were increased. Changes in the membrane permeability and altered abundance of sterols in the cell membrane were also observed.