Date of Award

2025

Document Type

Open Access Master's Thesis

Degree Name

Master of Science in Chemical Engineering (MS)

Administrative Home Department

Department of Chemical Engineering

Advisor 1

Rebecca G. Ong

Committee Member 1

David R. Shonnard

Committee Member 2

Timothy C. Eisele

Abstract

Polyethylene terephthalate (PET) is one of the most widely used polymers in plastics packaging. However, the increasing demand for PET has created challenges in waste disposal. Previous research has shown that PET can be deconstructed using ammonium hydroxide (CDPET). Microorganisms capable of utilizing the product as a sole carbon source can be converted to single-cell protein (SCP). A custom microbial inactivation unit was developed to ensure the safety and stability of generated SCP. Our study evaluated the effect of exposure time (45–60 minutes) at 140 °C with the goal of maximizing microbial inactivation. Our findings suggest that microbial inactivation can be achieved at 140 °C in 60 minutes. Since SCP is generated at relatively low concentrations, spray drying was investigated as a means to achieve rapid drying of heat-inactivated cell biomass. We analyzed spray drying parameters, such as inlet air temperature, feed flow rate, and nozzle pressure, to maximize SCP yield. Overall, the results of this study provide an effective method for recovering SCP from CDPET, with potential applications in the food and feed industries.

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