초록
<P><B>Abstract</B></P> <P>Low exoglucanase and endoglucanase activities of marine <I>Aspergillus niger</I> cellulase decreased the hydrolyzing ability of cellulase. To increase the activity of halostable cellulase obtained from a marine <I>A. niger</I>, a cellulase with endoglucanase and exoglucanase activity was efficiently expressed by constructing a vector with promoter <I>glaA</I>. Exoglucanase and endoglucanase activities increased from 0.21 and 4.51U/ml of the original strain to 0.89U/ml and 15.12U/ml of the transformant, respectively. Filter paper activity (FPA) increased by 7.1 folds from 0.63 to 4.47U/ml. The release of glucose by hydrolysis of wheat straw with cellulase from the transformant was 1.37 folds higher than that with cellulase from the original strain under high salinity condition. Cellulase with endoglucanase and exoglucanase activities could be well expressed in marine <I>A. niger</I>. The cellulase from the transformant not only showed higher activity, but also retained halostability. An appreciate proportion of β-glucosidase, exoglucanase, endgolucanasein cellulase was important for hydrolyzing cellulose.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Exoglucanase increased from original 0.21U/ml to 0.89U/ml of the transformant. </LI> <LI> Endoglcanase increased from original 4.51U/ml to 15.12U/ml of the tranformant. </LI> <LI> FPA increased nearly 7.1 folds from 0.63U/ml to 4.47U/ml. </LI> <LI> Cellulase from the transformant remained halostable ability. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>