Bacterial degradation of dehydropolymers of coniferyl alcohol.

A bacterial isolate identified as Xanthomonas sp. proved to be ligninolytic due to its ability to degrade 14C-labeled dehydropolymers of coniferyl alcohol (DHP) and [14C]lignocellulose complexes from corn plants (Zea mays). Several parameters of ligninolysis were evaluated and it was shown that resting cells degrade DHP as sole carbon source. Enhancement of DHP degradation in the presence of ferulic acid or water-soluble fractions of DHP or of dioxane lignin from wheat was demonstrated. It is shown that a dissociation of DHP takes place during incubation in the absence of the bacteria which is reflected in a shift of DHP to lower molecular weight fractions. Bacterial degradation of [14C]DHP results in the release of 14CO2 and in the incorporation of the 14C-label into the biomass of the bacteria, as shown by chemical and biological methods.