Transformation of cinoxacin by Beauveria bassiana.

The ability of the fungus Beauveria bassiana ATCC 7159 to transform the antibacterial agent cinoxacin was investigated. Cultures in sucrose-peptone broth were dosed with cinoxacin, grown for 20 days, and then extracted with ethyl acetate. Two metabolites were detected and purified by high-performance liquid chromatography. The major metabolite was identified by mass and proton nuclear magnetic resonance spectra as 1-ethyl-1,4-dihydro-3-(hydroxymethyl)[1,3]dioxolo[4,5-g]cinnolin-4-one and the minor metabolite was identified as 1-ethyl-1,4-dihydro-6,7-dihydroxy-3-(hydroxymethyl)cinnolin-4-one. B. bassiana also reduced quinoline-3-carboxylic acid to 3-(hydroxymethyl)quinoline.