Fungal oxidoreductases as biocatalysts for fine chemicals transformations

Fungal oxidoreductases are promising tools for the production of fine chemicals as pharmaceuticals, flavors and fragrances. In this study, 28 filamentous fungi, belonging to 24 genera, were tested in the bioconversion of methyl cinnamate; only Syncephalastrum racemosum, Cunninghamella bertholletiae and Mucor plumbeus reduced the C=C double bond and the carboxylic group showing ene reductase activity and carboxylic acid reductase activity, respectively. Since the latter activity has been poorly investigated in filamentous fungi, further analysis was conducted. Three strains of C. bertholletiae and nine strains of S. racemosum converted a carboxylic acid (phenoxyacetic acid) and its methyl ester (methyl phenoxyacetate). Interestingly no intraspecific difference could be highlighted. Most of S. racemosum strains completely reduced both compounds within two days; the strength of the expressed enzymatic pattern is confirmed by the fact that it was not perturbed by the nature of the original substrate.