Immobilization and Stabilization of a Cyclodextrin Glycosyltransferase by Covalent Attachment on Highly Activated Glyoxyl-Agarose Supports

Abstract

Covalent immobilization of cyclodextrin glycosyltransferase on glyoxyl-agarose beads promotes a very high stabilization of the enzyme against any distorting agent (temperature, pH, organic solvents). For example, the optimized immobilized preparation preserves 90% of initial activity when incubated for 22 h in 30% ethanol at pH 7 and 40 degrees C. Other immobilized preparations (obtained via other immobilization protocols) exhibit less than 10% of activity after incubation under similar conditions. Optimized glyoxyl-agarose immobilized preparation expressed a high percentage of catalytic activity (70%). Immobilization using any technique prevents enzyme inactivation by air bubbles during strong stirring of the enzyme. Stabilization of the enzyme immobilized on glyoxyl-agarose is higher when using the highest activation degree (75 micromol of glyoxyl per milliliter of support) as well as when performing long enzyme-support incubation times (4 h) at room temperature. Multipoint covalent immobilization seems to be responsible for this very high stabilization associated to the immobilization process on highly activated glyoxyl-agarose. The stabilization of the enzyme against the inactivation by ethanol seems to be interesting to improve cyclodextrin production: ethanol strongly inhibits the enzymatic degradation of cyclodextrin while hardly affecting the cyclodextrin production rate of the immobilized-stabilized preparation.

Cellulose Nanocrystal/Gold Nanoparticle Composite as a Matrix for Enzyme Immobilization

“…Less than 10% CGTase activity was detected in the supernatants at low enzyme loading (<25 000 U/g of CNC). At this enzyme loading, most of the activity (>90%) was associated with the CNC pellets such that the total recovery of the activity was close to 100%, compared to 70% or less on other supports (23,24). As the enzyme loading was increased (>25 000 U/g of CNC), the total activity recovered from the supernatants and pellets ranged from 67 to 82%.…”

Immobilization of Cyclodextrin Glucanotransferase fromPaenibacillus MaceransATCC 8244 on Magnetic Carriers and Production of Cyclodextrins

“…The enzyme was able to convert 63% of soluble starch (4%, w/v) to cyclodextrins (27). Using starch as substrate the maximum starch conversion to β-CD and γ-CD with immobilized thermostable CGTase on glyoxyl-agarose was 29% (14,59). The products obtained from different starches such as corn, wheat and potato as well as amylose and amylopectin were studied.…”

Cyclodextrin glucanotransferase production by cell biocatalysts of alkaliphilic bacilli

“…their properties like activity, resistance to inhibition by reaction products, selectivity towards non-natural substrates [14]. Different approaches have been applied for the immobilization of CGTases, based on adsorption [15], entrapment [16] or covalent binding [17][18][19]. Immobilization by physical adsorption or entrapment is generally unsuitable because the enzyme readily leaks from the support during the reaction.…”