Degradation of toluene by ortho cleavage enzymes in Burkholderia fungorum FLU100.
Bottom Line: This means that 2-ML is an intermediate of toluene degradation and converted by specific enzymes.The conversion of 4-methylcatechol as a very minor by-product of toluene degradation in strain FLU100 resulted in the accumulation of 4-carboxymethyl-4-methylbut-2-en-4-olide (4-methyl-2-enelactone, 4-ML) as a dead-end product, excluding its nature as a possible intermediate.Thus, 3-methylcyclohexa-3,5-diene-1,2-diol, 3-methylcatechol, 2-methyl muconate and 2-ML were identified as central intermediates of productive ortho cleavage pathways for toluene metabolism in B. fungorum FLU100.
Affiliation: Department of Biological Waste Air Purification, Institute of Sanitary Engineering, Water Quality and Solid Waste Management, University of Stuttgart, Bandtäle 2, Stuttgart, D-70569, Germany.Show MeSH
Related in: MedlinePlus
Mentions: To identify further intermediates of 2-ML degradation pathway, analyses were performed by use of HPLCs with an evaporative light scattering detector (HPLC-ELSD) or a mass spectrometer (HPLC-MS). However, neither metabolites of 2-ML degradation were reproducibly detectable nor identification of detected compounds was possible. 2-methyl succinate as hypothetical intermediate of the 2-ML degradation pathway, however, was used as a substrate in conversion experiments. Whereas the reference substrate succinate was transformed without showing any lag phase, methyl substituted succinate was not converted at all by whole cells of FLU100 (see Supporting Information Table S5). Therefore, revelation of the complete degradation pathway downstream of the intermediate 2-ML was not successful. Maximum conversion rates of the identified intermediates of toluene degradation by FLU100 pre-grown on toluene are given in Table 1. The correlating degradation pathway is shown in Fig. 4.
Affiliation: Department of Biological Waste Air Purification, Institute of Sanitary Engineering, Water Quality and Solid Waste Management, University of Stuttgart, Bandtäle 2, Stuttgart, D-70569, Germany.