Immobilized proteins with specific binding capacities and their use in processes and products

PCT No. PCT/EP94/00427 Sec. 371 Date Nov. 1, 1995 Sec. 102(e) Date Nov. 1, 1995 PCT Filed Feb. 10, 1994 PCT Pub. No. WO94/18330 PCT Pub. Date Aug. 18, 1994A method is provided for immobilizing a binding protein capable of binding to a specific compound, using recombinant DNA techniques for producing said binding protein or a functional part thereof. The binding protein is immobilized by producing it as part of a chimeric protein also comprising an anchoring part derivable from the C-terminal part of an anchoring protein, thereby ensuring that the binding protein is localized in or at the exterior of the cell wall of the host cell. Suitable anchoring proteins are yeast alpha -agglutinin, FLO1 (a protein associated with the flocculation phenotype in S. cerevisiae), the Major Cell Wall Protein of lower eukaryotes, and a proteinase of lactic acid bacteria. For secretion the chimeric protein can comprises a signal peptide including those of alpha -mating factor of yeast, alpha -agglutinin of yeast, invertase of Saccharomyces, inulinase of Kluyveromyces, alpha -amylase of Bacillus, and proteinase of lactic acid bacteria. Also provided are recombinant polynucleotides encoding such chimeric protein, vectors comprising such polynucleotide, transformed microorganisms having such chimeric protein immobilized on their cell will, and a process for carrying out an isolation process by using such transformed host, wherein a medium containing said specific compound is contacted with such host cell to form a complex, separating said complex from the medium and, optionally, releasing said specific compound from said binding protein.