Biotransformation of ethyl 2-(2′-nitrophenoxy)acetate to benzohydroxamic acid (D-DIBOA) by Escherichia coli

Benzohydroxamic acids, such as DIBOA, exhibit interesting biological properties (herbicidal, fungicidal and bactericidal). Recently, the synthesis of DIBOA has been simplified to only two steps. This paper explores the possibility of replacing the second stage in the chemical synthesis of D-DIBOA by a biotransformation using a strain of Escherichia coli and a strain of Serratia marcescens. Biotransformation experiments were carried out for both strains in the presence of different concentrations (0.25, 0.5 and 1 mg/mL) of the precursor (ethyl 2-(2′-nitrophenoxy)acetate) under aerobic and anaerobic conditions. Both strains tolerated the concentrations of precursor investigated here. Higher biotransformation yields were reached for E. coli under aerobic conditions. The UV/vis spectra and 1H/13C spectroscopic data obtained from HPLC-DAD and NMR, respectively, for the compounds obtained in the biotransformation reaction confirmed the presence of D-DIBOA in cultures of E. coli. The maximum yields were obtained in experiments supplemented with 0.5 mg/mL of precursor and these were 20.14 ± 1.87% under aerobic conditions and 8.17 ± 0.94% under anaerobic conditions.