Screening and degradation characterization of fosfomycin-degrading bacterial strains

Fosfomycin-degradation strains were isolated from acclimated activated sludge feeding fosfomycin as the sole carbon source. Three fosfomycin-degradation strains, named F1, F2 and F3, were screened out and their morphological observation, physiological and biochemical characteristics, as well as 16S rDNA sequence were analysed to identify the genus and the growth characteristics. Strain F3 had a faster growth adaptation period, and was selected to study the degradation of fosfomycin. The effects of operation parameters such as temperature and pH on fosfomycin degradation were explored, and the degradation process was fitted by the first-order kinetic equation. The results showed that strain F1 belonged to Microbacterium sp. and strain F2 and F3 both belonged to Cupriavidus sp. The degradation process of fosfomycin of strain F3 was affected by temperature and pH. The optimal conditions were pH 5.0 and temperature 20 ℃ when the inoculum was 20%, the rotation speed was 150 r/min, and the fosfomycin concentration was 20 mg/L. The degradation process fitted well with pseudo-first-order kinetic model, and the correlation coefficient R² exceeded 0.88. When pH was 5.0 and temperature was 20 ℃, the half-life period was 31.36 d.