A pure strain of Pseudomonas chlororaphis DJ-4 capable of anaerobic biodegradation of o-xylene, m-xylene and p-xylene was
isolated from gasoline contaminated soil. In batch cultures, growth of the strain and biodegradation of xylene isomers led to
stoichiometric reduction of nitrate. P. chlororaphis DJ-4 could degrade 150 mg L-1 of m-xylene completely within 12 days and
without a lag period. However, higher initial concentrations of o-xylene and p-xylene were toxic to the bacterium of P.
chlororaphis DJ-4, and showed a lag phase of 6 and 9 days, respectively. P. chlororaphis DJ-4 could growth well using xylene
isomers as carbon source, and about 6~9% of the substrate was used for bacterial growth. This is the first report of xylene
isomers biodegradation by a bacterium of P. chlororaphis under nitrate reducing conditions.