Efficiency of bovine liver catalase as a catalyst to cleave H₂O₂ added continually to buffer solutions

Abstract

Empirical estimations of H2O2 concentration in a system containing bovine liver catalase and continually supplied with H2O2 were done to evaluate the efficiency of the enzyme to cleave H2O2. It was found that the continuous addition of H2O2 leads to the formation of steady-state concentrations of H2O2 in the medium. At a constant catalase concentration both the level and the duration of the steady state are dependent on the flow rate of H2O2. The increase of the catalase concentration in the medium does not change the steady-state level, it merely leads to the maintenance of the steady state for longer durations. At higher flow rates of H2O2, no steady state could be maintained, even when catalase was present in high excess. The incomplete cleavage of H2O2 by catalase under these conditions is due to the low affinity of catalase toward H2O2 (high K m value, apparent K m = 0.1M H2O2) and to the rapid inactivation of the enzyme during the continuous addition of H2O2.

Hydrogen Peroxide in Biocatalysis. A Dangerous Liaison

“…In this sense, catalases are the preferred enzymes to destroy hydrogen peroxide, in many instances yielding water and oxygen [127]. These enzymes tend to be multimeric, with the problems on their stability that this fact raises [128], and may have an hemo group or some metal (i.e, Mn…”

Use of catalase from Escherichia coli in model experiments for oxygen supply of microorganisms with hydrogen peroxide

“…The experiments were performed with various ciD values, starting with 0.0176M H202/h, a flow rate sufficient to provide oxygen to a suspension of Alcaligenes eutrophus of 2 g dry wt/L. 8 The enzyme was stable within a period of 30 min up to 0.564111 H202/h. At flow rates above this, the enzyme began to denature, but not with an exponential time function.…”

Over‐pressurized bioreactors: Application to microbial cell cultures

“…There are several methods to enhance oxygen mass transfer rate to a culture: increasing air flow rate and/or stirring speed, or enriching inlet air with pure oxygen . Other nonconventional methods to enhance the oxygen supply include coimmobilization or mixed culture with oxygen‐producing photosynthetic algae, in situ generation of molecular oxygen with hydrogen peroxide and catalase, and the introduction of an immiscible phase of perfluorocarbons with high oxygen solubility. Nevertheless, these strategies are limited by one or more factors, namely, increased cost of downstream processing to remove the added chemicals, toxicity, chemical compatibility, competition for common nutrients, and complications in bioreactor design and operation …”