Cloning and Expression of β-1,3-1,4-glucanase Gene from Bacillus licheniformis

A gene encodingβ-glucanase from Bacillus licheniformis was cloned and expressed in Escherichia coli.. The whole length of the gene was 818 bp, including an ORF of 732 bp and encodeing 243 amino acids. The enzyme showed a molecular size of 27.35 kD and a pI of 8.31. The nucleotide sequence of the gene shared high degree of sequence similarity to that of B.pumilus and B.licheniformis accessed in GenBank, and their similarities were 99% and 94%respectively. The gene has been registered in Genank(Accession number is AY225317). The gene from recombinant cloning plasmid was subcloned into Bam HⅠand XhoⅠsite of expression plasmid pET-lic in E. coli . The recombinant expression plasmid was transformed into E. coli strain BL21. The result of SDS-PAGE showed that about 27 kD protein of theβ-1,3-1,4-glucanase was expressed in E.coli strain BL21. The enzyme activity of E.coli expressed strain was 67.34 U/mL, which was about 60-fold higher than that of original strain. The pH and temperature at the highest activity was found were pH 5~6 and 50 ℃ respectively. It’s a good material for gene engineering to construct highly active and thermophilic enzymatic gene.