Effects of Free or Immobilized Bacterium Stenotrophomonas acidaminiphila Y4B on Glyphosate Degradation Performance and Indigenous Microbial Community Structure.

The overuse of glyphosate has resulted in serious environmental contamination. Thus, effective techniques to remove glyphosate from the environment are required. Herein, we isolated a novel strain Stenotrophomonas acidaminiphila Y4B, which completely degraded glyphosate and its major metabolite aminomethylphosphonic acid (AMPA). Y4B degraded glyphosate over a broad concentration range (50-800 mg L-1), with a degradation efficiency of over 98% within 72 h (50 mg L-1). Y4B degraded glyphosate via the AMPA pathway by cleaving the C-N bond, followed by degradation of AMPA and subsequent metabolism. Y4B demonstrated strong competitiveness and substantially accelerated the degradation of glyphosate in different soils, degrading 71.93 and 89.81% of glyphosate (400 mg kg-1) within 5 days in sterile and nonsterile soils, respectively. The immobilized cells of Y4B were more efficient than their free cells and they displayed excellent biodegradation efficiency in a sediment-water system. Taken together, Y4B is an ideal degrader for the bioremediation of glyphosate-contaminated sites.