Ultrafine composite fibers of silicate-polymer matrix structure were synthesized by the combination of sol-gel chemistry and electrospinning to immobilize a tyrosinase enzyme for the purpose of continuous and/or reusable operations. These ultrafine enzyme-carrying fibers with average diameters of less than one micron were studied by their incorporation into a small-scale, flow-through micro-reactor to demonstrate the feasibility of phenol detection with simultaneous remediation through biocatalysis. Biocatalytic activity of the electrospun enzyme (tyrosinase) was confirmed and evaluated using the integrated form of the Michaelis-Menten equation, having the advantage of requiring fewer experimental runs than other approaches. Micro-Raman spectral analysis was also used to demonstrate biocatalysis and the possible biocomposite nature of the enzyme-carrying fibers. Biocatalytic activity of the electrospun enzyme was retained at phenol concentrations of 0.12-5 mM, typical of contaminated waters. This research demonstrates the potential of this cost-effective fibrous material for biocatalysis and detection applicable in environmental and industrial analysis and remediation. (C) 2011 Elsevier Ltd. All rights reserved.