Abstract
The inhibitory effect of β-CD on pullulanase which hydrolyzes α-1,6 glycosidic bond in starch to release more available linear substrates, limited substrate utilization thus influencing the yield of β-CD. Here, an aspartic acid residue (D465) which interacted with cyclodextrin ligand by hydrogen bond, was mutated to explore its contribution to bind inhibitors and obtain mutants with lower affinity to β-CD. Enzyme activity results showed that mutants D465E and D465N retained higher activity than wild-type pullulanase in presence of 10 mM β-CD. Circular dichroism spectra and fluorescence spectra results showed that D465 was related to structure stability. Chain length distribution results confirmed the improvement of substrate utilization by the addition of D465E. The conversion rate from potato starch, cassava starch, and corn starch into β-CD, increased to 56.9%, 55.4% and 54.7%, respectively, when synchronous using β-CGTase and D465E in the production process.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
