Degradation of Trimethylbenzene Isomers by an Enrichment Culture under N(inf2)O-Reducing Conditions.

A microbial culture enriched from a diesel fuel-contaminated aquifer was able to grow on 1,3,5-trimethylbenzene (1,3,5-TMB) and 1,2,4-TMB under N(inf2)O-reducing conditions, but it did not degrade 1,2,3-TMB. The oxidation of 1,3,5-TMB to CO(inf2) was coupled to the production of biomass and the reduction of N(inf2)O. N(inf2)O was used to avoid toxic effects caused by NO(inf2)(sup-) accumulation during growth with NO(inf3)(sup-) as the electron acceptor. In addition to 1,3,5-TMB and 1,2,4-TMB, the culture degraded toluene, m-xylene, p-xylene, 3-ethyltoluene, and 4-ethyltoluene.