초록
<B>Background:</B><P> The intensification of fermentation in stirred bioreactors is an attractive approach for commercial interests and industries that work with biochemical products. Alpha amylase is an enzymatic bio-products that is produced largely from <I>Aspergillus oryzae</I>. Using adaptable agitator can be an efficient way for stirred fermentation.</P><B>Objective:</B><P> This study, concentrated on enhancing the mixing process in order to intensify <I>Aspergillus oryzae</I> fermentation. A straight type of Maxblend<SUP>®</SUP> impeller was used as an agitator to investigate the incubation parameters compared with the use of a 6-blade double Rushton turbine.</P><B>Method:</B><P> Stirred fermentation was done in batch condition. Effect of flow pattern of mixing on fermentation parameters was investigated after each sampling.</P><B>Results:</B><P>The results showed that the Maxblend<SUP>®</SUP> significantly intensified both enzyme activity and growth rate at low and moderate rates of power consumption (<I>P</I>). The main reason for the decreases in the growth rate and the enzyme activity during agitation by the Rushton turbine at low and high <I>P</I>v was the lack of oxygen and mycelial damage, respectively. Additionally, use of the Maxblend<SUP>®</SUP> significantly intensified the <I>K</I>L<I>a</I> at low and moderate rates of power consumption.</P><B>Conclusion:</B><P> Axial and uniform mixing by Maxblend<SUP>®</SUP> impeller was resulted in improving the fermentation characteristics and enzyme activity.</P>