In biodegradation processes free enzymes often undergo deactivation. Thus, it is very important to
obtain highly stable enzymes by different methods. Immobilization allows for successful stabilization of many
multimeric enzymes by increasing the rigidity of the enzyme structure. This study aimed to evaluate some
environmental factors that affect catechol 1,2-dioxygenase from Stenotrophomonas maltophilia
in alginate hydrogel. The goal of the present work was to improve the functional stability of the enzyme by
increasing its structural rigidity.
Immobilization yield and expressed activity were 100% and 56%, respectively. Under the same
storage conditions, the activity of the immobilized enzyme was still observed on the 28th d of incubation
at 4°C,whereas the free enzymelost its activity after 14 d. The immobilized enzymerequired approximately 10°C
lower temperature for its optimal activity than the free enzyme. Immobilization shifted the optimal pH from8 for
the soluble enzymeto 7 for the immobilized enzyme. The immobilized catechol 1,2-dioxygenase showed activity
against 3-methylcatechol, 4-methylcatechol, 3-chlorocatechol, 4-chlorocatechol, and 3,5-dichlorocatechol. The
immobilization of the enzyme promoted its stabilization against any distorting agents: aliphatic alcohols,
phenols, and chelators.
The entrapment of the catechol 1,2-dioxygenase from S. maltophilia
KB2 has been shown to
be an effective method for improving the functional properties of the enzyme. Increased resistance to
inactivation by higher substrate concentration and other factors affecting enzyme activity as well as broadened
substrate specificity compared to the soluble enzyme, makes the immobilized catechol 1,2-dioxygenase suitable
for the bioremediation and detoxification of xenobiotic-contaminated environments.