An expression system is described for the production of monomeric scFvs and scFv antibody fragments genetically fused to human albumin (at either the N- or C-terminus or both). Based upon strains of Saccharomyces cerevisiae originally developed for the production of a recombinant human albumin (Recombumin (R)) this system has delivered high levels of secreted product into the supernatant of shake flask and high cell density fed-batch fermentations. Specific binding to the corresponding ligand was demonstrated for each of the scFvs and scFv-albumin fusions and pharmacokinetic studies showed that the fusion products had greatly extended circulatory half-lives. The system described provides an attractive alternative to other microbial systems for the manufacture of this type of product. (C) 2010 Elsevier Inc. All rights reserved,