Changes in cellular fatty acid composition during naphthalene degradation, at the concentrations of 0.5 g lñ1 or 1.0 g lñ1,by Pseudomonas sp. JS150 were investigated. In response to naphthalene exposure an increase in saturated/unsaturatedratio was observed. Additionally, the dynamic changes involved alterations in the contents of hydroxy, cyclopropaneand branched fatty acids. Among the classes of fatty acids tested the most noticeable changes in the abundance ofcyclopropane fatty acids were observed. Since day 4 of incubation these fatty acids were not dectected in bacterial cellsgrowing on naphthalene. In contrast, markedly increased in the percentage of hydroxy fatty acids over time wasobserved. However, the proportions of saturated straight-chain and branched fatty acids did not change such significantly
