초록
<P><B>Highlights</B></P><P>► We find a novel bacterial endoglucanase which has excellent properties. ► The endoglucanase is successfully overexpressed in <I>Bacillus subtilis</I>. ► The expression level is greatly enhanced by using the sucrose-inducible <I>sacB</I> promoter. ► We find the recombinant enzyme has improved resistibility to SDS. ► The recombinant enzyme is stable in laundry detergent and shows great potential in detergents industry.</P> <P><B>Abstract</B></P><P>An endoglucanase from <I>Bacillus akibai</I> I-1 was successfully overexpressed in <I>Bacillus subtilis</I> 168 and the expression level of the recombinant enzyme was greatly enhanced by using the sucrose-inducible <I>sacB</I> promoter. The endoglucanase activity in the culture supernatant of recombinant <I>B. subtilis</I> by using itself promoter (<I>Hpa</I>II) in plasmid pMA5 was 3U/ml. Interestingly, with the addition of <I>sacB</I> promoter at downstream from the <I>Hpa</I>II promoter or the replacement of <I>Hpa</I>II promoter by the <I>sacB</I> promoter, the endoglucanase activities reached 62 and 60U/ml, respectively, under the optimal culture conditions. These results demonstrated that the <I>sacB</I> promoter might be more efficient for the expression of the endoglucanase than the <I>Hpa</I>II promoter. More interestingly, the purified native enzyme had broad pH stability, good thermostability and resistibility to various metal ions and chelating agents examined, while the recombinant enzyme had improved resistibility to SDS, which was stable in 0.2% (w/v) laundry detergent and thus showed great potential in detergents industry.</P>