Hydrolysis of butteroil by immobilized lipase using a hollow‐fiber reactor: IV. Effects of temperature

Abstract

A lipase from Aspergillus niger, immobilized by adsorption on microporous polypropylene hollow fibers, was used to effect the hydrolysis of the glycerides of melted butterfat at pH. 7.0 at 40, 50, 55, and 60 degrees C. Mcllvane buffer was pumped upward through the lumen, and melted butterfat was pumped upward through the shell side of a hollow fiber reactor. Nonlinear regression methods were employed to determine the kinetic parameters of models based on combinations of three nested rate expressions for the hydrolysis reaction with three nested rate expressions for thermal deactivation of the enzyme. A rate expression containing four lumped parameters is sufficient to model the release of free fatty acids as a function of reactor space time and time elapsed after immobilization. Nonlinear regression methods were also employed in global fits of the data to rate expressions containing an explicit dependence on temperature. For the reaction conditions used in this research, a 14-parameter rate expression is necessary to accurately model the overall release of free fatty acids as a continuous function of the absolute temperature, initial substrate concentrations, reactor space time, and time elapsed after immobilization of the lipase.

Kinetics and mechanisms of reactions catalyzed by immobilized lipases☆

“…Fitting of rate expressions of this type usually becomes a matter of fitting ratios of polynomials; statistical decision on the degree of complexity required to fit a given data set should then be based on a model nesting procedure suggested by the various powers that appear in the polynomials, using extra sum of squares of residuals as diagnostic statistic [12]. Despite the usefulness and appropriateness of this procedure, it has received the attention of only a few researchers [9,30,49,52,53]. In the case of a single type of ester (i.e.…”

“…Malcata et al [47,49,50,52,53] have modeled their experimental data using a general Ping Pong Bi Bi mechanism Table 2 Rate constants of immobilized lipases based on the assumption of a Michaëlis-Menten Uni Uni mechanism Source of lipase and two nested simplifications thereof (i.e. deacylation-or acylation-controlling).…”

Lipase-Catalyzed Acidolysis of Butter Oil with Conjugated Linoleic Acid: A Kinetic Study Involving Multiple Reuse of the Immobilized Enzyme

“…However, to obtain plots that can be more readily interpreted, it is convenient to employ the concept of a pseudo-reaction time to permit representation of the data in two dimensions. 17 The pseudo-reaction time represents a mathematical combination of the time elapsed since the start of the first experiment in the series and the time elapsed during a particular trial. The pseudo-reaction time for a particular trial is defined as where t* is the pseudo-reaction time, t is a dummy variable, t 1 is the time at which processing of the particular batch of interest was initiated, and (t -t 1 ) is the (elapsed) time during which a particular batch of oil is in contact with the lipase (the actual reaction time).…”

Enzymatic membrane reactors: the determining factors in two separate phase operations

“…51 -53 Use of this biphasic EMR is highly attractive when HFM are employed. 54,55 The HFM modules have four separate openings, an inlet and an outlet for each side of the membrane as shown in Fig. 1, which allow continuous flows across the membrane surfaces.…”