Pseudomonas nitroreducens LY was immobilized in nanofibers by an electrospinning process. We studied the impact of polymer concentration on the electrospinning process, and we also studied the viability of the immobilized cells and their impact factors. Furthermore, theanine was synthesized by the immobilized P. nitroreducens LY. Fibers with an average diameter of 220 nm were obtained with 8% (w/v) polyvinyl alcohol (PVA) and a potential of 17 kV. The highest survival rate (30%) of the immobilized P. nitroreducens LY was achieved at this condition. The P. nitroreducens LY in the fibers was stored at 20 C for 3 months with no detectable decrease in cell viability. Using the nanofibers to immobilize P. nitroreducens LY, the theanine yield was 10.74 g/l with the conversion rate of sodium glutamate at 20.55%. Together, these results demonstrate the potential for application of advanced nanomaterials in microbial cell immobilizing technology by electrospinning. (C) 2010 Elsevier Ltd. All rights reserved.