A40926 is a natural glycopeptide antibiotic. It is a precursor of dalbavancin, a semi-synthetic second-generation glycopeptide in clinical development for the treatment of beta-lactam-resistant Staphyloccous aureus and Staphylococcus epidermidis infections. Deacylation of A40926, producing an intermediate useful for the synthesis of novel derivatives, can be carried out by the action of Actinoplanes teichomyceticus cells. Kinetics parameters for this particular deacylation reaction were obtained by fitting the experimental data to a Michaelis-Menten kinetic model. The feasibility of A40926 deacylation by immobilized A. teichomyceticus cells in an air-lift bioreactor was examined. A single continuously operated air-lift reactor (ALR) was evaluated by a model describing diffusion and reaction in the biocatalyst beads. Model estimates were in a good agreement with experimental results. The system was operated continuously for 21 days with overall conversion above 60%. (C) 2003 Elsevier Science Inc. All rights reserved.