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

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 x 10(-5) g L-1 to 1.0 x 10(-2) g L-1 (r=0.9984) with a detection limit of 2.1 x 10(-5) g L-1 (3 sigma). 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. (C) 2015 Elsevier B.V. All rights reserved.