Bio-Fenton reaction system facilitated by the H2O2-producing Desemzia sp. strain C1 degrades sulfonated polyethylene to oxalate

초록

Polyethylene is extremely recalcitrant in the environment due to its inert, long alkane chain structure without functional groups. For microbial biodegradation to occur, inert alkanes must be activated primarily by oxygen molecules under aerobic conditions, which require the cofactor NADH. Thus, the periplasmic or cytoplasmic bacterial oxygenase systems, which typically consume NADH, struggle to act on water-insoluble, inert, and longchain polyethylene, as it cannot penetrate the cell membrane. To break polyethylene into small organic acids, we adopted sulfonation and iron grafting pretreatment, followed by an advanced oxidation process facilitated by the high H2O2-producing Desemzia sp. strain C1. The optimized Bio-Fenton reaction system, comprising a bacterial culture medium containing the resting cells of strain C1 (OD600 = 2.5) and 25 mM lactate at pH 6.0, degraded iron-grafted sulfonated polyethylene (C/S ratio of 4) into the small organic acid oxalate, yielding 65 mu M over a 72 h incubation period. The identification of oxalate produced from 13C-labeled sulfonated polyethylene in the BioFenton reaction was confirmed by tracing the 13C-labeled isotopes using mass spectrometry. This study provides a simple solution to convert the globally problematic environmental pollutant polyethylene into fine organic acids through a bacteria-driven oxidative Fenton reaction facilitated by the high H2O2-producing Desemzia sp. strain C1.

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