Cloning and expression of β-1,4-endoglucanas gene from Symbiobacterium thermophilum

A gene encoding endoglucanase from S.thermophilum IAM 14863 was cloned and recombined into expression vector pET32a(+),then the recombinant vector pET32a-Glu was transformed and expressed in E.coli BL21(DE3)PLYS.Sequence analysis showed that the coding region length of the gene is 1 101 bp,which encodes 366 amino acids.The result of SDS-PAGE showed that the gene was effectively expressed in E.coli BL21(DE3) PLYS with relative molecular weight of 60 kDa.The enzyme activity was 103 U/mL after purification.Characterization of the expression product showed that the optimum pH value was about 5,and the optimum reaction temperature was at 55 ℃,and expression product displayed better thermal stability(about 75 ℃)and pH stability.