Trichlorethylene (TCE) and cis-1,2-dichloroethene (cDCE) are volatile organic compounds (VOCs) that are ubiquitous in the environment and cause health concerns. In addition, the non-degradable nature of conventional plastics causes many environmental problems. It is therefore necessary to identify the bacteria that can break down the toxic VOCs and convert them into biodegradable plastics. In this study we used the bacteria Cupriavidus sp. CY-1 for the breakdown of VOCs and for the production of biodegradable plastics, ie, Poly-β-hydroxybutyrate (PHB). The strain CY-1 grew when supplemented with TCE or cDCE along with the co-substrates phenol or Tween 80. TCE was co-oxidized and converted to CO. reduced2, and phenol degradation produced two metabolites, catechol and the breakdown products of catechol. TCE or cDCE was converted to PHB by CY-1 when supplemented with phenol. CY-1 exhibited the highest dry cell mass (CDM) when grown with cDCE (0.74 ± 0.09 g L-1) or TCE (0.68 ± 0.04 g L-1) together with phenol and Tween 80. CY-1 showed the highest PHB accumulation (350 ± 15 mg g-1 CDM) when incubated with cDCE, phenol and Tween 80. The PHB production was calculated based on the results of bacterial CDM and high pressure liquid chromatography. FT-IR, 1Dog 13th13 C NMR analyzes were performed to identify PHB. The thermal properties of PHB were confirmed by thermogravimetric and differential scanning calorimetric analysis. The chemical shifts of PHBs made from VOCs were almost the same as those of standard PHB; therefore, CY-1 could convert toxic VOCs into valuable chemicals like PHB.

Graphic summary: Cometabolic degradation of toxic trichloroethene or cis-1,2-dichloroethene with phenol and production of poly-β-hydroxybutyrate (PHB)

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