FIG. 3.

Structural requirements for detachment of the nonyl moieties of 4-nonylphenol isomers as C₉ alcohols during incubation with S. xenophaga Bayram. Only nonylphenol isomers with three alkyl groups at the benzylic position are metabolized to the corresponding C₉ alcohols and serve as growth substrates. Isomers with benzylic hydrogens (bold) do not undergo detachment of the nonyl moiety and do not serve as growth substrates. The numbering system is based on a proposal by Guenther et al. (submitted).