Transformation of iso-pentylbenzene by a biofilm-forming strain of Candida viswanathii TH1 isolated from oil-polluted sediments collected in coastal zones in Vietnam

Abstract

This work is aimed to assess the aerobic biotransformation of a branched side chain alkylbenzene, iso-pentylbenzene, by Candida viswanathii TH1. The yeast Candida viswanathii TH1 isolated from oil-polluted sediments collected in coastal zones in Vietnam exhibited as a strain that could better transform branched aromatic hydrocarbons in biofilm (pellicle) than in planktonic form. During incubation of TH1 as biofilm with iso-pentylbenzene, the seven intermediates produced were benzoic acid, phenylacetic acid, 2-methyl-4-phenyl-butan-1-ol, 2-hydroxy-phenylacetic acid, 2-methyl-4-phenylbutyric acid, succinic acid and iso-valerophenone as revealed by gas chromatography/mass spectra and high-performance liquid chromatography analyses. The occurrence of these intermediates showed that iso-pentylbenzene could be oxidized not only via mono- but also by a sub-terminal oxidation pathway. This is the first study on iso-pentylbenzene transformation by a biofilm-forming Candida viswanathii strain. The catabolic versatility of the biofilm-forming strain TH1 and its use for mono and sub-terminal oxidation during the transformation of iso-pentylbenzene enhance our understanding of the degradation of branched side chain phenylalkanes and give new insight into the potential role of such species in the transformation of other recalcitrant aromatic compounds.