Enzyme stabilization by linear chain polymers in ultrafiltration membrane reactors

Abstract

AbstractThe experimental results discussed in this article concern p‐nitrophenylphosphate hydrolysis by acid phosphatase in an Ultrafiltration membrane reactor. The basic conclusions drawn are: (1) Linking the enzyme to a soluble support does not give rise to an increase in its stability while the chemical manipulations involved result in marked reductions in enzymic activity. (2) Enzyme entrapment within a proteic gel produces a considerable increase in its thermal stability as compared to the diluted native enzyme; this presumably stems from drastic reductions in enzyme mobility. (3) Correspondingly, considerable reductions occur in enzyme activity that depend on substrate mass transfer resistances within the gel layer. (4) Small amounts of linear chain water‐soluble synthetic polymers (polyacrylamides) give rise to high macromolecular concentration levels in the reactor region where the enzyme is dynamically immobilized and produce the same enzyme stabilization as gel entrapment. (5) Only minor substrate mass transfer limitations take place in this region and hence enzyme activity is virtually unaffected. (6) Both effects (stabilization and slight activity reduction) seem not to depend strongly on the characteristics of the soluble polymer (molecular weight and ionic character).