Application of matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry for the identification of alkylphenol polyethoxylate-degrading bacteria in the environment

In order to clarify the usefulness of the S10-GERMS (S10-spc-alpha operon gene-encoded ribosomal protein mass spectrum) method for the discrimination of microbial isolates from the environment, the isolates with octylphenol polyethoxylate (OPEOn)-degrading capability from several soils in Japan were classified into 4 biodegradation patterns based on different final metabolic toxicants. Some isolates were identified as genera Chelatococcus and Mesorhizobium which have never been reported as OPEOn-degrading bacteria based on 16S rRNA gene sequences. The findings from this study demonstrate that the S10-GERMS method successfully discriminates the isolates at the strain level in the genus Pseudomonas. Moreover, this method is better than 16S rRNA gene sequence similarity because it precisely demonstrated that OPEOn-degrading bacteria in the genera Chelatococcus and Mesorhizobium might be new species. The S10-GERMS method is suggested as a useful tool for the discrimination and monitoring of man-made chemical-degrading bacteria isolated from the environment. (C) Pesticide Science Society of Japan