Phenol metabolism by two microorganisms isolated from Amazonian forest soil samples

Two microorganisms isolated from Amazonian forest soil samples and identifi ed as Candida tropicalis and Alcaligenes faecalis were capable of degrading phenol (16 and 12 mM, respectively) at high salt concentrations (15% and 5 .6%, respectively). Chromatographic and enzymatic studies revealed that eac h microorganism cleaved phenol at the ortho position with total phenol mine ralization. C-14-phenol mineralization assays showed that both microorganis ms assimilated about 30% of the total label. No phenol degradation metaboli te (i.e., catechol, cis, cis-muconic acid) was detected in the intercellula r medium. The presence of phenol hydroxylase (EC 1.14.13.7) and catechol 1, 2-dioxygenase (EC 1.13.11.1) extracellular activity suggested that these mi croorganisms may secrete these enzymes into the extracellular medium.