A Study on the Comparative Stability of Insoluble Complexes of Glucose Oxidase Obtained with Concanavalin A and Specific Polyclonal Antibodies

Coupling Self-Assembly Mechanisms to Fabricate Molecularly and Electrically Responsive Films

Biomacromolecules often possess information to self-assemble through low energy competing interactions which can make self-assembly responsive to environmental cues and can also confer dynamic properties. Here, we coupled self-assembling systems to create biofunctional multilayer films that can be cued to disassemble through either molecular or electrical signals. To create functional multilayers, we: (i) electrodeposited the pH-responsive self-assembling aminopolysaccharide chitosan, (ii) allowed the lectin Concanavalin A (ConA) to bind to the chitosan-coated electrode (presumably through electrostatic interactions), (iii) performed layer-by-layer self-assembly by sequential contacting with glycogen and ConA, and (iv) conferred biological (i.e., enzymatic) function by assembling glycoprotein (i.e., enzymes) to the ConA-terminated multilayer. Because the ConA tetramer dissociates at low pH, this multilayer can be triggered to disassemble by acidification. We demonstrate two approaches to induce acidification: (i) glucose oxidase can induce multilayer disassembly in response to molecular cues, and (ii) anodic reactions can induce multilayer disassembly in response to electrical cues.

Enzymatic biopolishing of cotton fabric with free/immobilized cellulase

Cotton fabric was biopolished using free and immobilized cellulase. The immobilized cellulase treatment results lower weight loss and minimum reduction in tensile strength of the fabric at the minimum of 67% and a maximum of 98.35% and better whiteness index when compared with free cellulase treatment. Regression analysis was carried out for all properties, regression coefficients and summary of fit have been discussed. Both free and immobilized cellulase treated fabrics showed improved crystallinity index and it was analyzed by XRD. FTIR spectra were obtained to measure the hydrogen bonding intensity, which showed that the intensity values were decreased after treatment. The study confirms that the treatment with immobilized cellulase improves the surface properties without affecting the strength of fabric than the fabric treated with free cellulase.

Calcium alginate entrapped preparation of α-galactosidase: its stability and application in hydrolysis of soymilk galactooligosaccharides

Thermostable α-galactosidase from Aspergillus terreus (GR) was insolubilized using concanavalin A obtained from jack bean extract and in order to maintain the integrity of complex in the presence of its substrate or products, this complex was crosslinked with glutaraldehyde. Soluble α-galactosidase entrapped in calcium alginate retained 82% of enzyme activity whereas, Con A-α-galactosidase complex entrapped in calcium alginate and crosslinked Con A-α-galactosidase complex entrapped calcium alginate retained 74 and 61% activity, respectively. A fluidized bed reactor was constructed for continuous hydrolysis of galactooligosaccharides in soymilk using crosslinked Con A-α-galactosidase complex entrapped calcium alginate. Optimum conditions such as pH (5.0) and temperature (65°C) were the same for all immobilized enzyme preparations and soluble enzyme. Crosslinked Con A-α-galactosidase entrapped complex exhibited enhanced thermostability and showed 62% of activity (38%) after 360 min at 65°C. Entrapped crosslinked Con A-α-galactosidase complex preparation was superior in the continuous hydrolysis of oligosaccharides in soymilk by batch processes compared to the other entrapped preparations. The entrapped crosslinked concanavalin A-α-galactosidase complex retained 95% activity after eight cycles of use.

Bioaffinity-based an inexpensive and high yield procedure for the immobilization of turnip (Brassica rapa) peroxidase

This study demonstrates the immobilization of carbohydrate containing turnip peroxidase on an inexpensive bioaffinity adsorbent, Concanavalin A-cellulose support. The bioaffinity support was prepared simply by incubating cellulose powder with jack bean extract at 4 degrees C. Cellulose powder adsorbed 30 mg concanavalin A/g of the matrix. Concanavalin A adsorbed cellulose has been employed for the simultaneous purification and immobilization of glycoenzymes directly from ammonium sulphate fractionated proteins of turnip. The obtained bioaffinity support was quite effective in high yield immobilization of peroxidase from turnip and it retained 672 U/g. Turnip peroxidase immobilized on concanavalin A-cellulose support retained 80% of the initial activity. Immobilized turnip peroxidase preparation was quite resistant against the denaturation mediated by pH, heat, urea, guanidinium-HCl, Surf Excel, cetyltrimethylammonium bromide and water-miscible organic solvents; dimethyl formamide, dioxane and n-propanol. Low concentration of detergents like Surf Excel and cetyltrimethylammonium bromide enhanced the activity of soluble and immobilized turnip peroxidase.