2.4. Hydrocarbons degradability test of the bacteria consortium
The hydrocarbon utilization ability of each isolate was tested with a variety of hydrocarbon substrates. The trials were carried out in MSM inoculated with a 2.0% (v/v) target strain after the medium sterilized at 120 °C for 30 min. The amount of respective sole carbon source using in this study was 0.005% (w/v) of solid hydrocarbons or 0.1% (v/v) of liquid substrates. Hydrocarbon substrates included toluene, xylene, naphthalene, paraffin oil, n-hexadecane, cyclohexane, hexane and crude oil. The pH was adjusted to 7.0–7.2. The cells were incubated at 25 °C with shaking at 130 rpm for 14 days. Cell density was used as a proxy to present the microbial growth condition.