Chitinases　play　an　important　role　in　the　process　of　chitin　bioavailability.　In　this　study,　we　cloned　a　new　chitinase　gene　and　characterized　its　recombinant　protein.　The　new1251　bp　gene　of　chitinase　(ChiT-7)　was　cloned　fromthe　metagenome　of　themangrove　tidal　flat　soil　in　the　city　of　Zhangzhou　in　Fujian　Province　(China)　by　genome　walking.　The　gene　encoded　amature　protein　with　381　amino　acids,　whichmanifested　certain　sequence　similarity　(59%　identity)　to　characterized　GH18　chitinases.　The　mature　protein　of　ChiT-7　was　successfully　expressed　in　E.　coli　BL21　(DE3).　After　purification,　the　specific　activity　of　the　recombinant　enzyme　was　0.63　U/mg　at　the　optimal　pH　of　6.0　and　the　optimal　temperature　of　45　degrees　C.　The　rChiT-7　was　active　over　a　wide　pH　range,　and　the　residual　enzyme　activity　reached　80%　or　higher　at　30　degrees　C-50　degrees　C.　rChiT-7　hydrolyzed　colloidal　chitin　with　(GlcNAc)(2)　and　GlcNAc　as　the　main　final　products.　Structural　analysis　of　ChiT-7　indicated　that　ChiT-7　could　be　a　processive　chitinase.　rChiT-7　manifested　characteristics　analogous　to　those　of　fungi　and　actinomycetes　and　exhibited　sequence　homology.　(c)　2020　Published　by　Elsevier　B.V.