Fig. 6

Metabolic pathways for degradation of dibenzofuran by Pseudomonas sp. strain ISTDF1. The scheme was proposed by Jaiswal et al. (2011) with a slight modification on the basis of metabolites recovered from the culture fluid. Compounds in parentheses (though not assayed) are unstable and spontaneously converted to their respective hydroxylated forms. Arrows designated with question marks are routes that are chemically not feasible. Most likely HOHPDA was converted to salicylic acid before being transformed to gentisic acid. Both gentisic acid and catechol may evolve from HOHPDA simultaneously. (1), Dibenzofuran-1,2-dioxygenase; (2), 1,2-dihydroxy-1,2-dihydrodibenzofuran dehydrogenase; (3), 1,2-dihydroxybenzofuran dioxygenase; (4), Dibenzofuran-4,4a-dioxygenase; (5), 4,4a-dihydroxy-4-hydro-dibenzofuran dehydrogenase, and (6), 2,2′,3-trihydroxybiphenyl dioxygenase