Shear induced inactivation of a-amylase in a plain shear field

M.E. van der Veen, D.G. van Iersel, A.J. van der Goot, R.M. Boom

Research output: Contribution to journalArticleAcademicpeer-review

29 Citations (Scopus)


A newly developed shearing device was used to study shear-induced inactivation of thermostable alpha-amylase in a plain shear field, under conditions comparable to extrusion. The results show that the inactivation can be described well with a first-order process, in which the inactivation energy largely depends on the shear stress, instead of specific mechanical energy or strain history. The resulting dependency of the rate of inactivation on the shear stress is very strong and nonlinear, which leads to the conclusion that in many cases the maximally applied shear stress determines the inactivation. Quantification of the inactivation rates gives design criteria for the application of enzymes in more viscous systems than conventionally used, provided that the reactor is designed such that no peak shear stresses occur.
Original languageEnglish
Pages (from-to)1140-1145
JournalBiotechnology Progress
Issue number4
Publication statusPublished - 2004


  • twin-screw extruder
  • enzymatic-hydrolysis
  • starch
  • deactivation
  • cellulase
  • reactor
  • transglutaminase
  • kinetics
  • enzymes
  • beta

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