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영어

In this study, we utilized a catabolite repressorto improve the enzymatic activity of recombinantb-galactosidase inclusion bodies (IBs) produced inEscherichia coli under the araBAD promoter system.Specifically, we employed methyl a-D-glucopyranoside(a-MG) to lower the transcription rate of the b-galactosidasestructural gene. In deepwell microtiter plate and labscalefermentor culture systems, we demonstrated that theaddition of a-MG after induction improved the specificb-galactosidase production, even though b-galactosidasewas still produced as an IB. Particularly, the addition of0.0025% a-MG led to the most significant increase in thespecific activity of the bgalactosidase. Interestingly, theb-galactosidase IBs obtained in the presence of 0.0025%a-MG were more loosely packed, as determined by IBsolubilization in guanidine hydrochloride solution. Wepropose that the reduced gene transcription rate wasresponsible for the increased specific b-galactosidaseactivity and the loose packing that characterized the IBsproduced in the presence of a-MG. This principle could beapplied throughout the enzyme bioprocessing industry inorder to enhance the activity of aggregate-prone enzymeswithin IBs.