Abstract: Abstract: [Objective]To screen endoglucanas gene with thermostability,and construct themostable engineering bacteria with high enzyme activity.[Methods]A gene encoding endoglucanase from S.thermophilum IAM 14863 was cloned and recombinanted into expression vector pET32a(+),then the recombinant vector pET32a-Glu was transformed and expressed in E.coli BL21(DE3)PLYS.[Results]The whole length of is 1101bp,which encodes 366 amino acids.The result of SDS-PAGE showed that the gene was effectively expressed in E.coli BL21(DE3)PLYS,and the enzyme showed that a molecular weight of 60kDa approximately.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. [Conclusion]The research first recombinanted β-1,4-endoglucanas gene from S.thermophilum into expression vector pET32a(+) and expressed highly in E. coli. It will lay the foundation for food,textile,chemical and other fields by widely using the enzyme.

Key words: cellulase ,  , &beta, -1,4-endoglucanas ,  , Symbiobacterium thermophilum , cloning , prokaryotic expression