Biodegradation of 1-alkoxy-2,4-dichlorobenzenes by Yarrowia lipolytica KCTC 17618

• Yarrowia lipolytica could rapidly transform alkoxybenzenes to phenoxyalkanoates.
• Short-chain alkoxybenzenes can be utilized as carbon source for growth.
• Metabolism of alkoxybenzenes follows β-oxidation mechanism.
• Valuable agrochemicals can be produced by Y. lipolytica.

Detailed analyses of the biodegradation of 1-alkoxy-2,4-dichlorobenzenes by Yarrowia lipolytica KCTC 17618 were conducted by gas chromatography-mass spectrometry. Eight different 1-alkoxy-2,4-dichlorobenzenes with a linear alkylgroup (butyl to tetradecyl) were subjected to liquid culture. Y. lipolytica could rapidly metabolize short-chain analogues (butyl to hexyl) and utilize them as the sole carbon source for growth, whereas the analogues with longer alkyl groups were unable to support the growth but gradually metabolized in the nutrient media. The metabolic rates decreased with an increase of alkyl chain length up to a decyl group. Comprehensive metabolite analysis indicated that 4-(2,4-dichlorophenoxy)-butyric acid was the final metabolite of substrates with even-numbered alkoxy groups. 4-(2,4-dichlorophenoxy)-butyric acid is a well-known plant growth regulator and herbicide. In case of odd-numbered alkoxybenzenes, 3-(2,4-dichlorophenoxy)-propionic acid was the most abundant metabolite and no trace of 4-(2,4-dichlorophenoxy)-butyric acid was observed. These findings suggested that alkyl chain metabolism by the yeast follows a typical β-oxidation mechanism. The metabolism was partially inhibited by piperonylbutoxide, a common cytochrome P450 inhibitor. Dose-dependent production of 4-(2,4-dichlorophenoxy)-butyric acid from 1-butoxy-2,4-dichlorobenzene was evaluated. The maximum yield was 487 mg l−1 at 1 g l−1 of substrate. In summary, Y. lipolytica could efficiently produce 4-(2,4-dichlorophenoxy)-butyric acid from 1-alkoxy-2,4-dichlorobenzenesthrough oxidative metabolism.