Stress responses of Acinetobacter strain Y during phenol degradation.

Quantification of gene expression of Acinetobacter strain Y under 1000 mg/l of phenol was investigated using qPCR and proteomic analyses. The results show that Acinetobacter strain Y utilized 100 % of phenol within 18 h of exposure. The results of qPCR and proteomic analyses demonstrate a sequential expression of phenol-degrading genes of Acinetobacter strain Y via the ortho-pathway followed by the β-ketoadipate pathway. Many stress-responsive proteins such as chaperones, chaperonins, porins and the enzymes involved in the signal transduction pathway were upregulated especially in the early stage. The stressed bacteria produced more ABC-type transporters, membrane receptors and efflux pumps to mitigate the impacts of phenol stress. The functions of TCA/glyoxylate cycle and oxidative phosphorylation processes were negatively affected. Many enzymes in the gluconeogenesis pathway were upregulated. This study demonstrates bacterial strategies of Acinetobacter strain Y via the energy saving mechanisms and the coordinated control between carbon (C)- and nitrogen (N)-limitations in coping with the stress by scavenging the reactive oxygen species.