Date of Award


Document Type

Open Access Master's Thesis

Degree Name

Master of Science in Biological Sciences (MS)

Administrative Home Department

Department of Biological Sciences

Advisor 1

Stephen Techtmann

Committee Member 1

Rebecca Ong

Committee Member 2

Rupali Datta


Plastic waste and human hunger pose major threats to the health and wellbeing of populations world-wide. Using microbial methods to upcycle polyethylene terephthalate (PET) plastic into value-added compounds such as single cell protein (SCP) for human consumption is a unique solution to both these issues. Two monomers of chemically deconstructed PET (DCPET), terephthalate (TPA) and ethylene glycol (EG), have been previously shown to be biodegradable by enriched microbial communities. Using this top-down knowledge to inform the reconstruction of a minimal microbial community constructed from isolated members of these communities is a novel way to efficiently process these monomers via a synthetic microbial community. This study combines Rhodococcus sp. TE21C, shown to be a generalist capable of degrading TPA but not ethylene glycol, and Paracoccus sp. RL32C, previously identified as an ethylene glycol specialist that can also degrade TPA. Rhodococcus sp. TE21C has been shown to have a sensitivity to ethylene glycol. Combining these two isolates in a co-culture grown under high ethylene glycol conditions, Paracoccus sp. RL32C dominates the community with a minor contribution from Rhodococcus sp. TE21C. Paracoccus sp. RL32C appeared to benefit from the co-culture and grow to a higher density under these conditions. When grown under conditions that replicate the composition of DCPET, Paracoccus sp. RL32C supports the growth of Rhodococcus sp. TE21C in media containing only EG. In conditions where TPA is present, however, Rhodococcus sp. TE21C outcompetes Paracoccus sp. RL32C. These minimal synthetic communities can identify microbial interactions and help inform the reconstruction of efficient synthetic communities to effectively degrade PET plastic.