Synthetic bacterial consortium for degradation of plastic pyrolysis oil waste

Abstract

AbstractThe plasic crisis is ominipresent, from littering macroplastic to reports that document plastic in every niche of this planet, including the human body. In order to achieve higher recycling quotas, especially of mixed plastic waste, pyrolysis seems to be a viable option. However, depending on the process parameters, plastic pyrolysis oil waste is encountered, which is difficult to valorize, due to the enormous spread of the molecules included. To reduce the molecular heterogeneity, we here artificially compounded, monitored, and optimized the performance of a bacterial consortium, which has the ability to tolerate organic pollutants and use them as energy and carbon sources for their own metabolic activity. The primary constituents of the here used plastic pyrolysis oil waste (PPOW) were alkanes and ε-caprolactam. The bacterial community exhibited noteworthy efficacy in eliminating alkanes of diverse chain lengths ranging from 71% to 100%. Additionally, within 7-days, the microbial community demonstrated a removal efficiency surpassing 50% for various aromatic hydrocarbons, along with complete eradication of ε-caprolactam and naphthalene. Besides, a back-propagation (BP) neural network method is applied to evaluate O2consumption as a measure of microbial activity. The insights gained were used to build a model, which is able to predict O2depletion in long-time experiments and other experimental conditions. The results are discussed in the context of a developing (open) circular plastic economy.Graphical abstractHighlightSynthetic bacterial communities are used to remove plastic hydrolysis oil wasteThe optimized biphase reaction system can remove the majority of pollutantsThe biodegradation process can be monitored in a real-time bioprocess softwareNeural network techniques are used to model and predict the removal process