Expression of a endo-cellulase gene from Clostridium thermocellum and characterization of its recombinant enzyme.

A gene encoding a endo-cellulase from C.thermocellum was cloned by PCR method.The open reading frame(ORF) of the gene was constitulted by 1 947 bp.The nucleotide sequence of the gene by BLAST analysis shared high homology to that of Clostridium thermocellum accessed in GenBank,and the similarity was 93%.The recombinant expression plasmid was transformed into E.coli strain BL21.The result of SDS-PAGE showed that about 77 kDa.The enzyme activity of E.coli expressed strain was 90 U/ml,which was about 2.8-fold higher than that of the original strain.The optimum pH value and temperature were 8 and 60 ℃ respectively.