Abstract
Candida tropicalis utilized phenol, catechol, and 3- and 4-methylcatechols for growth as sole carbon source, but did not utilize p-, m-, or o-cresols, or p-, m-, and o-hydroxybenzoates. The yeast cells, however, rapidly oxidized cresols without a lag period after incubation with phenol.
In a medium containing phenol, two major metabolites were accumulated, i.e., one, catechol and the other, the ring-cleaved metabolite of catechol, identified as C6H6O4. Therefore, it appears that the first step of the phenol oxidation by the yeast is monohydroxylation of phenol.
The metabolite from p- or m-cresol by phenol-adapted cells was isolated and identified as 5-formyl-2-hydroxy-4-methyl-2, 4-pentadienoic acid. The same compound was obtained from 4-methylcatechol used as substrate. It was suggested that p- and m-cresols were hydroxylated to form 4-methyl- catechol, followed by the cleavage with extra-diol type ring fission. The oxidation of o-cresol at slower rate was also demonstrated. The metabolite from o-cresol gave different UV absorption spectrum from that formed from 3-methylcatechol.
