Up-Cycling of PET (Polyethylene Terephthalate) to the Biodegradable Plastic PHA (Polyhydroxyalkanoate)

TLDR: The conversion of the petrochemical polymer polyethylene terephthalate to a biodegradable plastic polyhydroxyal-kanoate (PHA) is described here and PHA was detected in all three strains when nitrogen depleted below detectable levels in the growth medium.

Abstract: The conversion of the petrochemical polymer polyethylene terephthalate (PET) to a biodegradable plastic polyhydroxyalkanoate (PHA) is described here. PET was pyrolised at 450 °C resulting in the production of a solid, liquid, and gaseous fraction. The liquid and gaseous fractions were burnt for energy recovery, whereas the solid fraction terephthalic acid (TA) was used as the feedstock for bacterial production of PHA. Strains previously reported to grow on TA were unable to accumulate PHA. We therefore isolated bacteria from soil exposed to PET granules at a PET bottle processing plant. From the 32 strains isolated, three strains capable of accumulation of medium chain length PHA (mclPHA) from TA as a sole source of carbon and energy were selected for further study. These isolates were identified using 16S rDNA techniques as P. putida (GO16), P. putida (GO19), and P. frederiksbergensis (GO23). P. putida GO16 and GO19 accumulate PHA composed predominantly of a 3-hydroxydecanoic acid monomer while P. freder...