Model-based operational optimisation of a microbial bioprocess converting terephthalic acid to biomass

Abstract Polyethylene terephthalate (PET) is a major contributor to plastic pollution due to its widespread presence in synthetic fibres. As an intermediate in the chemical recycling of PET, disodium terephthalate (Na2TA) can be harnessed as a cheap microbial substrate for the cultivation of Pseudomonas sp. GO16. Here, we present the model-based optimisation of a liquid feeding regime with the purpose of improving the automation and operational ease of Na2TA conversion into Pseudomonas sp. GO16 biomass. The model was parameterised and validated using data from dynamic liquid-phase and solid-phase feeding experiments. The validated model identified sodium ion accumulation as a key determinant of bioprocess performance and was used to design a liquid-phase feeding strategy that maximises Pseudomonas sp. GO16 biomass synthesis. The obtained biomass concentrations of 10.5 g/L (liquid-phase feeding) and 15.3 g/L (solid-phase feeding) are the highest ever reported using Na2TA as a sole carbon source for microbial growth.