Taxonomic significance of polyamine synthesis in Paracoccus.

Five Paracoccus species, P. denitrificans, P. alcaliphilus, P. aminophilus, P. aminovorans and P. kocurii, ubiquitously contained putrescine and spermidine as major polyamines. Spermine and cadaverine were detected sporadically in some strains as a minor component. All the strains of these species produced norspermidine from diaminopropane supplemented into the medium and some strains produced two aminopropyl derivatives of cadaverine, i.e., aminopropylcadaverine and aminopentylnorspermidine. The biosynthetic ability of these unusual polyamines serves as a chemotaxonomic marker in the genus Paracoccus. P. denitrificans IFO 13301 decarboxylated ε-N-methyllysine as well as lysine but neither ε-N-acetyllysine nor δ-hydroxylysine. The orgranism formed 2-hydroxyspermidine from the supplemented 2-hydroxyputrescine as well as 2-hydroxynorspermidine from 2-hydroxydiaminopropane but not N-acetyispermidine and N-methylspermidine from N-acetylputrescine and N-methylputrescine, respectively. A halophilic species, P. halodenitrificans, which contains spermidine as the major polyamine and has no norspermidine- and aminopropylcadaverine-synthetic potential, was suggested not to be a valid member of the genus Paracoccus.