Molecular study on cloned endoglucanase gene from rumen bacterium.

An endoglucanase gene was subcloned from anaerobic rumen bacterium Ruminococcus flavefaciens strain 17. To express endoglucanase gene in Escherichia coli and Streptococcus bovis JB1, an endoglucanase gene fragment was inserted into pVA838-based shuttle vectors. Removal of endoglucanase gene promoter and expression of endoglucanase by promoter of S. bovis JB1 alpha-amylase gene (pACMCS) was also achieved. Survival of constructs pVACMCI, pTACMC and pACMCS, which carry endoglucanase gene, and stability of endoglucanase gene in S. bovis JB1, were observed. Maximal endoglucanase activities from S. bovis JB1/pVACMCI were 2- to 3-fold higher than from E. coli/pVACMCI. Specific cell activity of E. coli/pACMCS was found to be approximately 2- to -3 fold higher than the both E. coli/pVACMCI and E. coli/pTACMC. Specific cell activity of S. bovis JB1/pACMCS was also found to be approximately 2-fold higher than the both S. bovis/pVACMCI and S. bovis JB1/pTACMC.