Genomic analysis of Acinetobacter pittii CEP14 reveals its extensive biodegradation capabilities, including cometabolic degradation of cis-1,2-dichloroethene.

Abstract

Halogenated organic compounds are naturally occurring in subsurface environments; however, accumulation of the degradative intermediate cis-1,2-dichloroethene (cDCE) at soil and groundwater sites contaminated with xenobiotic chlorinated ethenes is a global environmental and public health issue. Identifying microorganisms capable of cDCE degradation in these environments is of interest because of their potential application to bioremediation techniques. In this study, we sequenced, assembled, and analyzed the complete genome of Acinetobacter pittii CEP14, a strain isolated from chloroethene-contaminated groundwater, that has demonstrated the ability for aerobic cometabolic degradation of cDCE in the presence of n-hexane, phenol, and toluene. The A. pittii CEP14 genome consists of a 3.93Mbp-long chromosome (GenBank accession no. CP084921) with a GC content of 38.9% and three plasmids (GenBank accession no. CP084922, CP084923, and CP084924). Gene function was assigned to 83.4% of the 3,930 coding DNA sequences. Functional annotation of the genome revealed that the CEP14 strain possessed all genetic elements to mediate the degradation of a range of aliphatic and aromatic compounds, including n-hexane and phenol. In addition, it harbors gene clusters involved in cytosol detoxification and oxidative stress resistance, which could play a role in the mitigation of toxic chemical intermediates that can arise during the degradation of cDCE. Gene clusters for heavy metal and antibiotic resistance were also identified in the genome of CEP14. These results suggest that CEP14 may be a versatile degrader of xenobiotic compounds and well-adapted to polluted environments, where a combination of heavy metal and organic compound pollution is often found.