Whole-cell method for phenol detection based on the color reaction of phenol with 4-aminoantipyrine catalyzed by CotA laccase on endospore surfaces.

Abstract A green method for phenol spectrophotometric determination was developed based on the color reaction of phenol with 4-aminoantipyrine catalyzed by addition of Bacillus amyloliquefaciens endospores in the presence of O 2 . The catalytic activity of the endospores may be attributed to the presence of coat protein A on the cell surfaces. This deduction was confirmed by cotA gene knock-out from B. amyloliquefaciens using the homologous double-exchange method. Under optimal conditions, linear responses were obtained over phenol concentrations ranging from 5.0×10 −5  g L −1 to 1.0×10 −2  g L −1 ( r =0.9984) with a detection limit of 2.1×10 −5  g L −1 (3 σ ). Repeatability measurements of 1.0 mg L −1 phenol provided reproducible results with a relative standard deviation of 5.3% ( n =11). Standard addition tests indicated recoveries ranging from 92.78% to 107.60%. The proposed whole-cell method was successfully used to detect total phenol in synthetic samples. Results confirmed the potential use of the developed method in practical applications.