[The influence on the biodegradation of phenanthrene by nonionic surfactant, Tween20].

The objective of this study was to quantify the bioavailability of phenanthrene solubilized in surfactants by a mixed phenanthrene-degrading culture isolated from the petroleum contaminated soils. An nonionic surfactant, Tween20, was used. The effects of Tween20 on the microbial degradation of phenanthrene were evaluated depending on the rotary flasks experiments. The results showed that the concentrations of Tween20 above the critical micelle concentration (CMC) could increase the solubility of phenanthrene on great extent and were not toxic to the phenanthrene-degrading bacteria, and that the presence of surfactant micelles did not inhibit the biodegradation of phenanthrene. Phenanthrene solubilized in the micelles of Tween20 in liquid media was bioavailable and degradable by the mixed culture of bacteria.