In various embodiments a system is provided that displays heterologous proteins on the surface of a Gram-positive microorganism. In certain embodiments the system displays proteins using a sortase transpeptidase to covalently anchor proteins to the cell wall of the microbe. Novel bacterial strains are provided to exploit this system to display cellulase enzymes and multi-enzyme complexes on the surface of Gram-positive microorganisms (e.g., Bacillus subtilis) through their non-covalent interaction with a scaffoldin protein that is covalently anchored to the cell wall by the sortase transpeptidase. The surface displayed protein complexes contain enzymes capable of degrading cellulose into its component sugars at accelerated rates as compared to solutions of purified enzymes.
STATEMENT OF GOVERNMENTAL SUPPORT
 This invention was made with Government support under Grant No DE-FC02-02ER63421 awarded by the Department of Energy. The Government has certain rights in this invention.