A Bacillus spore cortex-lytic enzyme with the cell wall-binding activity,MbA,was used to develop a novel cell-surface display system of Bacillus thuringiensis.The full-length of mbA gene from B.thuringiensis wild-type strain YBT-9602 genome was PCR-amplified,sequenced and the structural features of its encoding domains were characterized.It showed that the predicted protein MbA was structurally distinguished by an N-terminal domain with peptidoglycan-binding activity and a C-terminal domain with cell wall-hydrolysis activity.By constructing and expressing the fused mbA-gfp,it showed that the heterologous GFP was successfully immobilized onto the surface of B.thuringiensis cells through the immunofluorescence microscopic observation and the assays of pronase accessibility and SDS sensitivity.Furthermore,the recombinant B.thuringiensis cells expressing the MbA-fused chimeric protein with a bacterial β-1,3-1,4-glucanase,were determined the surface-display efficiency using flow cytometry analysis,which showed that a 42.97% recombinant cells exhibited surface-displaying activity.The whole-cell enzymatic activity of the recombinant B.thuringiensis MB220 expressing the mbA-glS fusion gene was detected to be 13.5 U/mL.These results indicated that the MbA protein can be served as a functional carrier protein for developing a novel B.thuringiensis cell-surface display system.