Trans-membrane transport of fluoranthene by Rhodococcus sp. BAP-1 and optimization of uptake process

•A new strain was identified as Rhodococcus sp. BAP-1.•Demonstrated the mechanism for fluoranthene travel across bacteria cell membrane.•Transport dynamic combined with RSM to screen the significant variables.•Plackett–Burman design was used to screen the significant variables.•Box–Behnken design was employed to optimize the trans-membrane transport process.

The mechanism of transport of 14C-fluoranthene by Rhodococcus sp. BAP-1, a Gram-positive bacterium isolated from crude oil-polluted soil, was examined. Our finding demonstrated that the mechanism for fluoranthene travel across the cell membrane in Rhodococcus sp. BAP-1 requires energy. Meanwhile, the transport of fluoranthene involves concurrent catabolism of 14C, that leading to the generation of significant amount of 14CO2. Combined with trans-membrane transport dynamic and response surface methodology, a significant influence of temperature, pH and salinity on cellular uptake rate was screened by Plackett–Burman design. Then, Box–Behnken design was employed to optimize and enhanced the trans-membrane transport process. The results predicted by Box–Behnken design indicated that the maximum cellular uptake rate of fluoranthene could be achieve to 0.308 μmol min−1 mg−1·protein (observed) and 0.304 μmol min−1 mg−1·protein (predicted) when the initial temperature, pH and salinity were set at 20 °C, 9% and 1%, respectively.