Amperometric phenol biosensor based on a thermostable phenol hydroxylase.
Phenol hydroxylase (EC 1.14.13.7) was produced using Bacillus stearothermophilus in a 5-1 batch fermentation leading to approximately 17 units after 6 h. The partially purified phenol hydroxylase was entrapped in a sol-gel matrix. The enzyme-loaded silica gel was attached to the sensitive top of a Clark-type oxygen electrode and its application as a phenol biosensor was tested. There was linearity between the maximal rate of oxygen consumption and phenol concentration in the range between 2.5 and 400 microM at 40 degrees C and pH 7.6. The signal could be read off after 10 s at a concentration of 400 microM phenol. The sensor lost 20% of its activity within 7 days. Para-substituted phenols were not detectable.
Metzger
J
J
Department of Biotechnology, Aachen University of Technology, Germany. j.metzger@biotec.rwth-aachen.de
Reiss
M
M
Hartmeier
W
W
D015374:Biosensing Techniques; D002021:Buffers; D002138:Calibration; D004563:Electrochemistry; D004795:Enzyme Stability; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D016014:Linear Models; D006899:Mixed Function Oxygenases / Q000096:biosynthesis*; D009243:NAD / Q000032:analysis; D019800:Phenol / Q000032:analysis*; D013379:Substrate Specificity; D013696:Temperature
D002021:Buffers; D009243:NAD; D019800:Phenol; D006899:Mixed Function Oxygenases; C022336:phenol 2-monooxygenase