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 O2. 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 (3σ). 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.